Testing the Sony a7III for Astrophotography


Milky Way Rising at Dino Park

I put the new Sony a7III mirrorless camera through its paces for the features and functions we need to shoot the night sky.

Sony’s a7III camera has enjoyed rave reviews since its introduction earlier in 2018. Most tests focus on its superb auto exposure and auto focus capabilities that rival much more costly cameras, including Sony’s own a7rIII and a9. 

For astrophotography, none of those auto functions are of any value. We shoot everything on manual. Indeed, the ease of manually focusing in Live View is a key function. 

In my testing I compared the Sony a7III to two competitive DSLRs, the Canon 6D MkII and Nikon D750.

All three are “entry-level” full-frame cameras, with 24 to 26 megapixels and in a similar price league of $1,500 (Nikon) to 2,000 (Sony). 

I tested a Sony a7III purchased locally. It was not supplied to me by Sony in return for an “influential” blog post.

I did this testing in preparation for the new third edition of my Nightscapes and Time-Lapse eBook, which will include information on Sony mirrorless cameras, as well as many, many other updates and additions!

NOTE: Click or Tap on most images to bring them up full-frame for inspection.

Milky Way Rising at Dino Park
MILKY WAY AT DINOSAUR PARK A stack of 2 x 90-second exposures for the ground, to smooth noise, and at f/2.8 for better depth of field, plus a single 30-second untracked exposure at f/2 for the sky. All with the Laowa 15mm lens and Sony a7III at ISO 3200.

Mirrorless vs. DSLR

Sony a7III with Loawa 15mm
COMPACT CAMERA and LENS
The Sony a7III with the compact but fast Laowa Venus Optics 15mm f/2 lens.

 

As with Sony’s other popular Alpha 7 and 9 series cameras, the new Alpha 7III is a full-frame mirrorless camera, a class of camera Canon and Nikon have yet to offer, though models are rumoured or promised. 

In the meantime, Sony commands the full-frame mirrorless market.

As its name implies, a mirrorless camera lacks the reflex mirror of a digital single lens reflex camera that, in a DSLR, provides the light path for framing the scene though the optical viewfinder. 

Sony Live View
SONY LIVE VIEW
The Sony a7III’s excellent Live View screen display. You can see the Milky Way!

In a mirrorless, the camera remains in “live view” all the time, with the sensor always feeding a live image to either or both the rear LCD screen and electronic viewfinder (EVF). While you can look through and frame using the EVF as you would with a DSLR, you are looking at an electronic image from the sensor, not an optical image from the lens. 

The advantage of purely electronic viewing is that the image you are previewing matches the image you’ll capture, at least for short exposures. The disadvantage is that full-time live view draws more power, with mirrorless cameras notorious for being battery hungry. 

Other mirrorless advantages include:

  • Compact size and lighter weight, yet offering all the image quality of a full-frame DSLR.
  • The thinner body allows the use of lenses from any manufacturer, albeit requiring the right adapter, an additional expense.
  • Lenses developed natively for mirrorless models can be smaller and lighter. An example is the Laowa 15mm f/2 I used for some of the testing.
  • The design lends itself to video shooting, with many mirrorless cameras offering 4K as standard, while often in DSLRs only high-end models do.
  • More rapid-fire burst modes and quieter shutters are a plus for action and wedding photographers, though they are of limited value for astrophotography.

Points of Comparison

Camera Trio-Sony, Nikon, Canon
CAMERA TRIO
The Sony a7III, Nikon D750, and Canon 6D Mark II. Note the size difference.

In testing the Sony a7III I ignored all the auto functions. Instead, I concentrated on those points I felt of most concern to astrophotographers, such as:

  • Noise levels
  • Effectiveness of Long Exposure Noise Reduction (LENR) 
  • Quality of Raw files, such as sharpness of stars
  • Brightness of Live View for framing and focusing
  • Uniformity of sensor illumination
  • Compatibility for time-lapse imaging
  • Battery life

TL;DR Conclusions

Sony a7III and Meade 70mm
DEEP-SKY TEST
The North America Nebula with the Sony a7III and a Meade 70mm f/5 astrographic refractor, for a single 4-minute exposure at ISO 1600. The reds have been boosted in processing.

Noise
Levels of luminance and chrominance noise were excellent and similar to – but surprisingly not better than – the Nikon D750.

Star Eater
The Star Eater is gone. Stars are not smoothed out in long exposures. 

ISO Invariance 
The Sony exhibited good – though not great – “ISO invariant” performance.

Dark Frames 
Dark frame subtraction using Long Exposure Noise Reduction removed most – but not all – hot pixels from thermal noise. 

Live View Focusing and Framing
Live View was absolutely superb, though the outstanding Bright Monitoring function is as well-hidden as Sony could possibly make it. 

Sensor Illumination Uniformity
The Sony showed some slight edge-of-frame shadowing from the mask in front of the sensor, as well as a weak purple amp glow.

Features 
• The a7III lacks any internal intervalometer or ability to add one via an app. But it is compatible with many external intervalometers and controllers.

• The a7III’s red sensitivity for recording H-Alpha-emitting nebulas was poor. 

• It lacks the “light-frame” buffer offered by full-frame Canons that allows shooting several frames in quick succession even with LENR turned on.

Video Capability 
The a7III offers 4K video and, at 24 frames-per-second, is full-frame. Shutter speeds can be as slow as 1/4-second, allowing real-time aurora shooting at reasonable ISO speeds. 

Battery Life
Shooting typical 400-frame time-lapses used about 40% of the battery capacity, similar to the other DSLRs. 

Overall Recommendations
The Sony a7III is a superb camera for still and time-lapse nightscape shooting, and excellent for real-time aurora videos. It is good, though not great, for long-exposure deep-sky imaging. 

Liberty Schoolhouse with Star Trails
STAR TRAILS and AURORA With the Laowa 15mm lens and Sony a7III, for 155 exposures, all 20 seconds at f/2.8 and at ISO 800, and taken as part of a 360-frame time-lapse.

Noise

The Sony a7III uses a sensor that is “Backside Illuminated,” a feature that promises to improve low-light performance and reduce noise. 

I saw no great benefit from the BSI sensor. Noise at typical astrophoto ISO speeds – 800 to 6400 – were about equal to the four-year-old Nikon D750. 

That was a bit surprising. I expected the new BSI-equipped Sony to better the Nikon by about a stop. It did not. This emphasizes just how good the Nikon D750 is. 

Nevertheless, noise performance of the Sony a7III was still excellent, with both the Sony and Nikon handily outperforming the Canon 6D MkII, with its slightly smaller pixels, by about a stop in noise levels. 

NOTE: I performed all Raw developing with Adobe Camera Raw v10.3. It is possible some of the artifacts I saw are due to ACR not handling the a7III’s .ARW files as well as it should. But to develop all the images from Sony, Nikon, and Canon equally for comparisons, ACR is the best choice. 

1-Sony vs Nikon vs Canon Noise
COMPARING NOISE
The Sony a7III exhibited noise levels similar to the Nikon D750 at high ISOs, with the Sony and Nikon each about a stop better for noise than the Canon 6D MkII.
2A-Sony vs Nikon vs Canon at 3200
NOISE AT ISO 3200
At ISO 3200, a common nightscape ISO speed, all three cameras performed well in this moonlit scene. The Canon shows a darker sky as its images were taken a few minutes later. The Nikon had the Sigma 14mm Art lens; the Canon and Sony used the same Rokinon 14mm SP lens.
2B-Sony vs Nikon vs Canon at 6400
NOISE AT ISO 6400
At ISO 6400, the Canon begins to show excessive noise, about a stop worse than the Nikon and Sony. No luminance noise reduction was applied to these images. All cameras show an equal number of stars recorded.

ISO Invariance

Both the Sony and Nikon use sensor and signal path designs that are “ISO invariant.” As a result, images shot underexposed at slower ISOs, then boosted in exposure later in processing look identical to properly exposed high-ISO images. Well, almost.

The Sony still showed some discoloration artifacts and added noise when boosting images by +4 EV that the Nikon did not. Even with uncompressed Raws, the Sony was not quite as ISO invariant as the Nikon, though the difference shows up only under extreme push-processing of badly underexposed frames. 

Plus, the Sony was far better than the Canon 6D MkII’s “ISO variant” sensor. Canon really needs to improve their sensors to keep in the game. 

3A-Sony vs Nikon vs Canon ISO Invariancy
ISO INVARIANCE COMPARISON
Here I shot all three cameras at ISO 6400 for a correct exposure for the scene, and also at ISO 1600 and ISO 400, for images 2 and 4 stops underexposed respectively. These were then boosted in Adobe Camera Raw by 2 and 4 stops in Exposure Value (EV) to compensate. With ISO invariant sensors the boosted images should look similar to the well-exposed image.
3B-Sony vs Nikon vs Canon ISO Invariancy CU
ISO INVARIANCE CLOSE-UP
A closeup of the scene shows the ISO variant Canon exhibited more noise and magenta discoloration in the +4 EV boosted image. The Nikon looks very clean, but the Sony also shows discoloration, green here, and an increase in noise. These are all uncompressed 14-bit Raw files.
4-Sony vs Nikon ISO Invariancy
SONY vs. NIKON
Comparing just the two ISO-invariant cameras, the Sony and the Nikon, on another night, shows a similar performance difference when boosting underexposed slow-ISO images later in Camera Raw. The Sony begins to show more noise and now a magenta discoloration in the +3 and +4 EV images, similar to, but not as badly as does the ISO-variant Canon 6D MkII.

Compressed vs. Uncompressed 

Sony-Comp-UnCompThe Sony a7III offers a choice of shooting Uncompressed or Compressed Raw files. Uncompressed Raws are 47 Mb in size; Compressed Raws are 24 Mb. 

In well-exposed images, I saw little difference in image quality. 

But the dark shadows in underexposed nightscapes withstood shadow recovery better in the uncompressed files. Compressed files showed more noise and magenta discoloration in the shadows. 

It is not clear if Sony’s compressed Raws are 12-bit vs. 14-bit for uncompressed files. 

Nevertheless, for the demands of nightscape and deep-sky shooting and processing, I suggest shooting Uncompressed Raws. Use Compressed only if you plan to take lots of time-lapse frames and need to conserve memory card space on extended shoots. 

5A-Sony UnCompressed vs Compressed at -1EV
UNCOMPRESSED vs. COMPRESSED
Here I compare any image degradation from using compressed vs. uncompressed Raws, and from employing Long Exposure Noise Reduction. Images are only slightly underexposed and boosted by +1 EV in Camera Raw. Shadow noise is similar in all images, with the ones taken with LENR on showing elimination of colored hot pixels, as they should.
5B-Sony UnCompressed vs Compressed at -4EV
UNCOMPRESSED vs. COMPRESSED at -4EV
The same scene but now underexposed by 4 stops and boosted by +4 EV later shows greater differences. The compressed image shows more noise and discoloration, and the images taken with LENR on, while eliminating hot pixels, show more random luminance noise. Keep in mind, these are vastly underexposed images. 
6-Sony Comp vs Uncomp + DF
UNCOMPRESSED vs. COMPRESSED DEEP-SKY
A real-world deep-sky example shows the same comparison. All images are well-exposed, for tracked and guided 4-minute exposures. The ones taken with LENR on show fewer hot pixels. The compressed images appear identical to the uncompressed files for noise and star content.

Star Eater (Updated June 3, 2018)

Over the last year or so, firmware updates from Sony introduced a much-publicized penchant for Sony Alphas to “eat” stars even in Raw files, apparently due to an internal noise reduction or anti-aliasing routine users could not turn off. Stars were smoothed away along with the noise in exposures longer than 3.2 seconds in some Sony cameras (longer than 30 seconds in others).

I feel that in the a7III the Star Eater has been largely vanquished.

As the images below show, there is a very slight one-pixel-level softening that kicks in at 4 seconds and longer but it did not eat or wipe out stars. Stars are visible to the same limiting magnitude and close double stars are just as well resolved across all exposures. Indeed, at slower ISOs and longer exposures, more stars are visible.

I saw none of the extreme effects reported by others with other Sonys, where masses of faint stars disappeared or turned into multi-colored blotches.

I did not see any significant “star eating” in any long exposures even up to the 4 minutes I used for some deep-sky shots. In images taken at the same time with other cameras not accused of star eating, the Sony showed just as many faint stars as the competitors. Long exposures showed just as many stars as did short exposures.

This was true whether I was shooting compressed or uncompressed Raws, with or without Long Exposure Noise Reduction. Neither compression nor LENR invoked “star eating.” 

Sony-Star Eater Series @ 200%
STAR EATER SERIES at 200%
This series of tracked images (shown here blown up 200%) goes from 2 seconds to 2 minutes, with decreasing ISO speed to equalize the exposure value across the series. Between 3.2s and 4s a very slight one-pixel-level softening does kick in, reducing noise and very slightly blurring stars. Yet, just as many stars are recorded and are resolved, and at the lower ISOs/longer exposures more stars are visible because faint stars are not lost in the noise.
Sony-Star Eater Series @ 400%
STAR EATER SERIES at 400%
This is the same series as above but now blown up 400% to better reveal the very subtle change in pixel-level sharpness as exposure lengthened from 3.2 to 4 seconds. Noise (most noticeable in the trees) is reduced and stars are very slightly softened. But none are “eaten” or wiped out. And star colors are not affected, though very small stars are sometimes green, an effect seen in other cameras due to de-Bayering artifacts.
7A-Sony vs Canon for Star Eater v1
STAR EATER DEEP-SKY #1
Tracked deep-sky images through a telescope using 4-minute exposures show the Sony a7III recording an equal number of faint stars as the Canon 6D MkII. No luminance noise reduction was applied to these images in processing.
7B-Sony vs Canon for Star Eater v2
STAR EATER DEEP-SKY #2
Another example with 4-minute exposures again demonstrates no problems recording faint stars. The Canon does show more noise than the Sony. No noise reduction was applied in processing. 
7C-Sony vs Nikon for Star Eater
SONY and NIKON COMPARED
For yet more evidence, this is a comparison of the Sony a7III vs. the Nikon D750 in tracked 90-second exposures with 14mm lenses. Again, the Sony records just as many stars as the Nikon.

LENR Dark frames 

Sony-LENRFor elimination of hot pixels from thermal noise I prefer to use Long Exposure Noise Reduction when possible for nightscape and deep-sky images, especially on warm summer nights.

Exceptions are images taken for star trail stacking and for time-lapses, images that must be taken in quick succession, with minimal time gap between frames.

Turning on LENR did eliminate most hot pixels in long exposures, but not all. A few remained. Also, when boosting the exposure a lot in processing, the images taken with LENR on showed more shot and read noise than non-LENR frames. 

The dark frame the camera was taking and subtracting was actually adding some noise, perhaps due to a temperature difference. The cause is not clear. 

Sony advises that when using LENR Raw images are recorded with only 12-bit depth, not 14-bit. This might be a contributing factor. Yet frames taken with LENR on were the same 47 Mb size as normal uncompressed frames.

For those who think this is normal for LENR use, the Nikon D750 shows nothing like this – frames taken with LENR on are free of all hot pixels and do not show more shot or read noise, nor deterioration of shadow detail from lower bit depths.

However, I emphasize that the noise increase from using LENR with the Sony was visible only when severely boosting underexposed images in processing. 

In most shooting situations, I found using LENR provided the overriding positive benefit of reducing hot pixels. It just needs to be better, Sony!

8A-Sony Dark Frames (W and WO LENR)
SONY WITH AND WITHOUT LENR
These are 4-minute exposures of dark frames (i.e. the lens cap on!) taken at room temperature with and without Long Exposure Noise Reduction. In the Sony, LENR did not eliminate all hot pixels nor the magenta amp glow at the left edge. LENR also added a background level of fine noise. These have had exposure and contrast increased to exaggerate the differences.
8B-Nikon Dark Frames (W and WO LENR)
NIKON WITH AND WITHOUT LENR
Dark frames taken with the Nikon D750 under the same circumstances and processed the same show none of the residual hot pixels and added background noise when LENR is employed. Nor is there any amp glow anywhere along the frame edges.
8C-Sony With and Without LENR
SONY REAL-WORLD LENR COMPARISON
A real-world example with the Sony, with a properly exposed nightscape, shows that the ill effects of using LENR don’t show up under normal processing. You do get the benefit of reduced hot pixels in shadows, especially on a warm night like this was. This is a blow-up of the lower corner of the frame, as indicated.

Sensor Illumination 

How evenly an image is illuminated is a common factor when testing lenses. 

But astrophotography, which often requires extreme contrast boosts, reveals non-uniform illumination of the sensor itself, regardless of the optics, originating from hardware elements in front of the sensor casting shadows onto the sensor. 

This is most noticeable – indeed usually only noticeable – when shooting deep-sky targets though telescopes. 

With DSLRs it is the raised mirror which often casts a shadow, produced a dark vignetted band along the bottom of the frame. Its extent varies from camera model to model.

With a mirrorless camera the sensor is not set far back in a mirror box, as it is in a DSLR. As such, I would have expected a more uniformly illuminated sensor. 

Sony a7III - Sensor CU
SENSOR CLOSE-UP showing intruding mask edges.

Instead, I saw a slight shadowing at the top and bottom edges but just at the corners. This is from a thin metal mask in front of the sensor. It intrudes into the light path ever so slightly. It shouldn’t. 

This isn’t a serious flaw, and applying “flat fields” or ad hoc local adjustments would eliminate this.

However, long deep-sky exposures also exhibited a faint purple glow at the left edge, probably from heat from nearby electronics, a so-called “amp glow.” Taking a dark frame with LENR did not eliminate this, and it should, demonstrating again that for whatever reason in the a7III LENR is not as effective as it should be. 

I haven’t seen amp glows in cameras (at least in the DSLRs I’ve used) for a number of years, so seeing it in the new Sony a7III was another surprise. 

This would be tougher to eliminate in deep-sky images where the extreme contrast boosts we typically apply to images of nebulas and galaxies will accentuate any odd glows. 

9A-Sony Full Field
SONY FIELD ILLUMINATION #1
The full field of a deep-sky image taken through an f/5 70mm astrographic refractor shows the minor level of edge darkening at the corners from shadowing of the sensor in the Sony.
9B-Sony a7 III Vignetting
SONY FIELD ILLUMINATION #2
Another example taken in twilight to accentuate frame illumination shows the same shadow vignetting and the slight magenta amp glow at the left.

Red Sensitivity

When shooting deep-sky objects, particularly red nebulas, we like a camera to have a less aggressive infrared cutoff filter, to pick up as much of the deep red Hydrogen-Alpha emission line as possible. 

The Sony showed poor deep-red sensitivity, though not unlike other cameras. It was a little worse than the stock Canon 6D MkII. 

This isn’t a huge detriment, as anyone who really wants to go after deep nebulosity must use a “filter-modified” camera anyway. 

Canon and Nikon both offered factory modified cameras at one time, notably the Canon 60Da and Nikon D810a. Sony doesn’t have an “a” model mirrorless.

To get the most out of the Sony for deep-sky imaging you would have to have it modified by a third-party, such as Hutech, Spencers, or LifePixel though, as of this writing, none list the Sony a7III as a model they can modify.

10-Canon5D vs 6D vs Sony (Red Nebula)
RED SENSITIVITY COMPARED
Three deep-sky exposures compare cameras for red sensitivity: a filter-modified Canon 5D MkII, a stock Canon 6D MkII, and the stock Sony a7III. As expected the filter-modified camera picks up much more red nebulosity. The Sony doesn’t do quite as well as the Canon 6D MkII.

Live View Focusing and Framing 

Up to now my report on the Sony a7III hasn’t shown as glowing a performance as all the YouTube reviews would have you believe. 

But Live Focus is where the a7III really stands out. I love it!

In Live View it is possible to make the image so bright you can actually see the Milky Way live on screen! Wow! This makes it so easy to frame nightscapes and deep-sky fields.  

Sony-Custom Buttoms
FINDING BRIGHT MONITORING
The excellent Bright Monitoring function is accessible only off the Custom Key menu where it appears as a choice on the Display/Auto Review2 page (below) that can be assigned to a C button.

But this special “Bright Monitoring” mode is as well hidden as Sony could make it. Unless you actually read the full-length 642-page PDF manual (you have to download it), you won’t know about it. Bright Monitoring does not appear in any of the in-camera menus you can scroll through, so you won’t stumble across it.

Instead, you have to go to the Camera Settings 2 page, then select Still Image–Custom Key. In the menu options that appear you can now scroll to one called Bright Monitoring. Surprise! Assign it to one of the hardware Custom C buttons. I put it on C2, making it easy to call up when needed. 

Sony-Bright Monitoring

The other Live View function that works well, but also needs assigning to a C button is the Camera Settings 1 > Focus Magnifier. I put this on C1. It magnifies the Live View by 5.9x or 11.7x, allowing for precise manual focusing on a star. 

Sony-LiveViewDisp

Two other functions are useful for Live View: 

  • Camera Settings 2 > Live View Display > Setting Effect ON. This allows the Live View image to reflect the camera settings in use, better simulating the actual exposure, even without Bright Monitoring on.
  • Camera Settings 1 > Peaking Setting. Turning this ON superimposes a shimmering effect on parts of an image judged in focus. This might be an aid, or an annoyance. Try it. 

In all, the Sony provides superb, if well-hidden, Live View options that make accurately framing and focusing a nightscape or time-lapse scene a joy. 


Great Features for Astrophotography 

Here are some other Sony a7III features I found of value for astrophotography, and for operating the camera at night. 

Sony a7III with Tilt Screen
SONY TILTING SCREEN It tilts up and down but does not flip out as with the Canon 6D MkII’s. Still, this is a neck- and back-saving feature for astrophotography.

Tilting LCD Screen 
Like the Nikon D750, the Sony’s screen tilts vertically up and down, great for use when on a telescope, or on any tripod when aimed up at the sky. As photographers age, this becomes a more essential feature!

Sony-CustomKey

Custom Buttons 
The four C buttons can be programmed for oft-used functions, making them easy to access at night. Standard functions such as ISO and Drive Mode are easy to get at on the thumb wheel, unlike the Nikon D750 where I am forever hunting for the ISO or Focus Zoom buttons, or the Canon 6D MkII which successfully hides the Focus Zoom and Playback buttons at night.

Sony-MyMenu

My Menu 
In new models, Sony now offers the option of a final “My Menu” page which you can populate with often-used functions from the other 35 pages of menu commands!

Adaptability to Many Lenses 
Using the right lens adapter (I use one from Metabones), it is possible to use lenses with mounts made for Canon, Nikon, Sigma and others. Plus there are an increasing number of lenses from third parties offered with native Sony E-mounts. This is good news, as astrophotography requires fast, high-quality lenses, and the Sony allows more choices.

Lighter Weight / Smaller Size
The compact a7III body weighs a measured 750 grams, vs. 900 grams each for the Nikon D750 and Canon 6D MkII. The lower weight can be helpful for use on lightweight telescopes, on small motion control devices, and for simply keeping weight and bulk down when traveling. 

Sony a7III - Dual Slots

Dual Card Slots 
Not essential, but having two card slots is very helpful, for backup, for handling overflows from very long time-lapse shoots, or assigning them for stills vs. movies, or Raws vs. JPGs. Only Slot 1 will work with the fastest UHS II cards that are needed for recording the highest quality 4K video.

USB Power 
It is possible to power the camera though the USB port (indeed that’s how you charge the battery, as no separate battery charger is supplied as standard, a deficiency). This might be useful for long shoots, though likely as not that same USB port will be needed for an intervalometer or motion control device. But if the Sony had a built-in intervalometer…!

Sony-DispInfo

Display Options
To reduce battery drain it is possible to turn off the EVF completely – I find I never use it at night – and to turn off the LCD display when shooting, though the latter is an option you have to activate to add to the Display button’s various modes. 

The downside is that when shooting is underway you get no reassuring indication anything is happening, except for a brief LED flash when an image is written to a card.  

Sony-ECurtain

Electronic Front Curtain Shutter
Most DSLRs do not offer this, but the Sony’s option of an electronic front curtain shutter and the additional Silent Shooting mode completely eliminates vibration, useful for some high-magnification shooting through telephotos and telescopes.

11-Sony Shutter Vibration
LUNAR CLOSE-UPS COMPARED
This trio compares closeups of the Moon taken with and without electronic front curtain shutter. All were taken through a 130mm refractor telescope at f/12 using a Barlow lens. The image with e-shutter and in Silent Mode is a tad sharper, but that could be just as much from variations in seeing conditions as from the lower vibration from using the electronic shutter.

What’s Missing for Astrophotography

Intervalometer 
For all the Sony’s 35 pages of Menu functions, a built-in Intervalometer isn’t one of them. While it does have a 1 frame-per-second movie mode in its “Slow-and Quick” functions, that’s not sufficient for night time-lapses, plus S&Q mode only works with HD movies, not 4K.

A built-in intervalometer is not essential, since in time-lapse shooting we often use external controllers anyway. But I find I often do use the Canon and Nikon in-camera intervalometers for simple shoots, and for cold winter aurora shoots. How tough would it be to add it, Sony?

Bulb Timer or Long Exposures
While the Sony has a Bulb setting there is no Bulb Timer as there is with the Canon. The Bulb Timer would allow setting long Bulb exposures of any length in the camera. 

Instead the Sony must be used with an external Intervalometer. I use a $50 Vello unit, and it works very well. It controls the Sony through the camera’s Multi USB port.

In-Camera Image Stacking 
Also missing, and present on most new Canons, are Multiple Exposure modes for in-camera stacking of exposures in a Brighten mode (for star trails) or Averaging mode (for noise smoothing). 

Yes, this can all be done later in processing, but having the camera do the stacking can often be convenient, and great for beginners, as long as they understand what those functions do, or even that they exist!

Time-Lapse Smoothing 
When using its internal intervalometer, the Nikon D750 has an excellent Exposure Smoothing option. This does a fine job smoothing frame-to-frame flickering in time-lapses, something the Canon cannot do. Nor the Sony, as it has no intervalometer at all.

Light Frame Buffer in LENR
This feature is little known and utilized, and only Canon full-frame cameras offer it. Turn on LENR and it is possible to shoot three (with the 6D MkII) or four (with the 6D) Raw images in quick succession even with LENR turned on. The Canon 5D series also has this. 

The dark frame kicks in and locks up the camera only after the series of “light frames” are taken. This is wonderful for taking a set of noise-reduced deep-sky images for later stacking. Nikons don’t have this, not even the D810a, and not Sonys. 

Illuminated Buttons 
The Sony’s buttons are not illuminated. While these might add glows to long exposure images, if they could be designed not to do that (i.e. they turn off during exposures), lit buttons would be very handy at night. 

Limited Touch Screen Functions 
An alternative would be an LCD screen that was touch sensitive. The Sony a7III’s screen is, but only to select an area for auto focus or zooming up an image in playback. The Canon 6D MkII has a fully functional touch screen which can be, quite literally, handy at night.  

Sony a7III with Vello Intervalometer
INTERVALOMETER
For time-lapses, the Sony must be used with an external intervalometer like this Vello unit.

Video Capability 

Here’s another area where the new Sony a7III really shines. 

It offers 4K (or more precisely UltraHD) video recording for videos of 3840 x 2160 pixels. (True 4K is actually 4096 x 2160 pixels.)

With a fast enough UHS-II Class card it can record 4K video up to 30 frames per second and at a bit rate of either 60 or 100 Mbps. 

Sony-MovieSetting

At 24 fps videos are full-frame with no cropping. Hurray! You can take full advantage of wide-angle lenses, great for auroras. At 30 fps, 4K videos are cropped with a 1.2x crop factor.

In Movie Mode ISO speeds go up to ISO 102,400, but are pretty noisy, if unusable at such speeds. 

But when shooting aurora videos I found, to my surprise, I could “drag” the shutter speeds as slow as 1/4-second, fully 4 stops better than the Nikon’s slowest shutter speed of 1/60 second in Full HD, and 3 stops better than the Canon’s slowest movie shutter of 1/30 second. 

Coupled with a fast f/1.4 to f/2 lens, the slow shutter speed allows real-time aurora shooting at “only” ISO 6400 to 12,800, for quite acceptable levels of noise. I am very impressed! 

Real-time video of auroras is not possible with anything like this quality with the Nikon (I’ve used it often), and absolutely not with the Canon. And neither are 4K. 

Is the a7III as good for low-light video as the Sony a7s models, with their larger 8.5-micron pixels? 

I would assume not, but not having an a7s (either Mark I or II) to test I can’t say for sure. But the a7III should do the job for bright auroras, the ones with rapid motion worth recording with video, plus offer 24 megapixels for high-quality stills of all sky subjects. 

I think it’s a great camera for both astrophoto stills and video.

12A-Aurora Video Screen Shot
AURORA VIDEO FRAME
This is a frame grab from a real-time 4K video of a “Steve” aurora.

An example is in a 4K video I shot on May 6, 2018 of an usual aurora known as “STEVE.”

Steve Aurora – May 6, 2018 (4K) from Alan Dyer on Vimeo.


For another example of using the Sony a7III for recording real-time video of the night sky see this example of the Space Station crossing the sky.

Lilac Passages of the ISS (4K) from Alan Dyer on Vimeo.


Sony a7III - Buttons and Dials

Battery Life

I found the a7III would use up about about 40% of the battery capacity in a typical 400-frame time-lapse on mild spring nights, with 30-second exposures. This is with the EVF and rear LCD Display OFF, and the camera in Airplane mode to turn off wireless functions to further conserve battery power. I was using the wired Vello intervalometer. 

This is excellent performance on par with the DSLRs I use. At last, we have a mirrorless camera that not only doesn’t eat stars, it also does not eat batteries! 

One battery can get you through a night of shooting, though performance will inevitably decline in winter, as with all cameras. 

Planets Along the Ecliptic
MILKY WAY and PLANETS With the Sony a7III and Laowa 15mm lens at f/2 for a stack of 4 exposures for the ground to smooth noise and one exposure for the sky, all 30 seconds at ISO 3200.

Lens and Telescope Compatibility 

As versatile as a mirrorless camera is for lens choice, making use of that versatility requires buying the right lens adapter(s). They can cost anywhere from $100 to $400. The lowest cost units just adapt the lens mechanically; the more costly units also transfer lens data and allow auto focusing with varying degrees of compatibility. 

Sony a7III with MetaBones
WITH METABONES CANON ADAPTER
The MetaBones Canon EF-to-Sony E mount adapter transfers lens data and allows auto focus to function.

For use on telescopes, the simple adapters will be sufficient, and necessary as many telescope-to-camera adapters and field flatteners are optimized for the longer lens flange-to-sensor distance of a DSLR. Even if you could get a mirrorless camera to focus without a lens adapter to add the extra spacing, the image quality across the field might be compromised on many telescopes. 

I used the Metabones Canon-to-Sony adapter when attaching the Sony to my telescopes using my existing Canon telescope adapters. Image quality was just fine. 

Sony a7III with Telescope Adapter
ADAPTING TO A TELESCOPE
The MetaBones adapter, as will other brands, adds the correct lens flange to sensor distance for telescope field flatteners to work best.

Time-Lapse Controller Compatibility 

Due to limitations set by Sony, controlling one of their cameras with an external controller can be problematic. 

Devices that trigger only the shutter should be fine. That includes simple intervalometers like the Vello, the Syrp Genie Mini panning unit, and the Dynamic Perception and Rhino sliders, to name devices I use. However, all will need the right camera control cable, available from suppliers like B&H. 

And, as I found, the Sony might need to be placed into Continuous shooting mode to have the shutter fire with every trigger pulse from the motion controller. When used with the Genie Mini (below) the Sony fired at only every other pulse if it was in Single shot mode, an oddity of Sony’s firmware.

Some time-lapse controllers are able to connect to a camera through its USB port and then adjust the ISO and aperture as well, for ramped “holy grail” sunset-to-Milky Way sequences. 

For example, the TimeLapse+ View (see http://www.timelapseplus.com) works great for automated holy grails, but the developer recommends that with most Sonys the minimum allowed interval between shots is longer (8 to 14 seconds) than with Canons and Nikons. See http://docs.view.tl/#camera-specific-notes 

With the Alpine Laboratories Radian2, exposure ramping is not possible with a Sony, only basic shutter triggering. See https://alpinelaboratories.com/pages/radian-2-support-get-started_s 

Sony a7III on Genie Mini
SONY WITH THE SYRP GENIE MINI
The Sony A7III worked well with the Syrp Genie Mini motion controller with the right shutter cable but only when placed in Continuous mode.

Recommendations 

In conclusion, here’s my summary recommendations for the three competitive cameras, rating them from Poor, to Fair, to Good, to Excellent. 

Sony a7III - Angled Front

SONY: I deducted marks from the Sony a7III for deep-sky imaging for its lack of a light frame buffer, poor red sensitivity, odd LENR performance, and amp glow not seen on the other cameras and that dark frames did not eliminate. 

However, I did not consider “star eating” to be a negative factor, as the Sony showed just as many stars and as well-resolved as did the competitors, and what more could you ask for?

I rate the Sony excellent for nightscape imaging and for real-time aurora videos. I list it as just “good” for time-lapse work only because it will not be fully compatible with some motion controllers and rampers. So beware!

Nikon D750 Angled Front

NIKON: I deducted points for real-time video of auroras – the D750 can do them but is pretty noisy with the high ISOs needed. Its red sensitivity is not bad, but its lack of a light frame buffer results a less productive imaging cycle when using LENR on deep-sky shooting. 

I know … people shoot dark frames separately for subtracting later in processing. However, I’ve found these post-shoot darks rarely work well, as the dark frames are not at the same temperature as the light frames, and often add noise or dark holes. 

Canon 6D MkII Angled Front

CANON: The 6D MkII’s lack of an ISO invariant sensor rears its ugly head in underexposed shadows in dark-sky nightscapes. I like its image stacking options, which can help alleviate the noise and artifacts in still images, but aren’t practical for time-lapses. Thus my Good rating for nightscapes but Fair rating for time-lapses. (See my test at https://amazingsky.net/2017/08/09/testing-the-canon-6d-mark-ii-for-nightscapes/)

While the 6D MkII has HD video, it is incapable of any low-light video work.

But … when well exposed, such as in tracked deep-sky images, the 6D MkII performs well. (See my test at https://amazingsky.net/2017/09/07/testing-the-canon-6d-mkii-for-deep-sky/)

And its light-frame buffer is great for minimizing shooting time for a series of deep-sky images with in-camera LENR dark frames, which I find are the best for minimizing thermal noise. Give me a Canon full-frame any day for prime-focus deep-sky shooting. 

It’s just a pity the 6D MkII has only a 3-frame buffer when using LENR. Really Canon? The 2008-vintage 5D MkII had a 5-frame buffer! Your cameras are getting worse for astrophotography while Sony’s are getting better. 

SONY a7III NIKON D750 CANON 6D Mk II
Nightscapes

Excellent 

Excellent  Good
Time-Lapse Good  Excellent  Fair
Real-Time Video (Auroras) Excellent  Fair  Poor
Wide-field Deep Sky Good  Good  Excellent 
Telescopic Deep Sky Good  Good  Excellent 

I trust you’ll find the review of value. Thanks for reading!


ADDENDUM as of JUNE 6, 2018

Since publishing the first results a number of people commented with suggestions for further testing, to check claims that:

  1. The Sony would perform better for noise under dark sky conditions, at high ISOs, rather than the moonlit scene above. OK, let’s try that.
  2. The Sony would perform better in an ISO Invariancy “face-off” if its ISOs were kept above 640, to keep all the images within the Sony’s upper ISO range of its dual-gain sensor design, with two ranges (100 to 400, and 640 on up). Fair enough.
  3. What little “star-eater” effect I saw might be mitigated by shooting on Continuous drive mode or by firing the shutter with an external timer. That’s worth a check, too.

For the additional tests, I shot all images within a 3-hour span on the night of June 5/6, using the Sony a7III, Nikon D750, and Canon 6D MkII, with the respective lenses: the Laowa 15mm lens at f/2, the Sigma 14mm Art at f/2, and the Rokinon 14mm SP at f/2.5.

The cameras were on a Star Adventurer Mini tracker to keep stars pinpoints, though the ground blurred in the longer exposures.


DARK SKY NOISE TEST

I show only the Sony and Nikon compared here, shot at the common range of ISOs used for nightscape shooting, 800 to 12800. All images are equally well exposed. The inset image at right in Photoshop shows the scene, the Milky Way above dark trees in my backyard!

To the eye, the Sony and Nikon look very similar for noise levels, just as in the moonlit scene. Both are very good – indeed, among the best performing cameras for high-ISO noise levels. But the Sony, being four years newer than the Nikon, is not better.

BUT … what the Sony did exhibit was better details in the shadows than the Nikon.

And this was with equal processing and no application of Shadow Recovery. This is where the Sony’s Backside Illuminated sensor with presumably higher quantum efficiency in gathering photons might be providing the advantage. With its good shadow details, you have to apply less shadow recovery in post-processing, which does keep noise down. So points to Sony here.

Sony vs Nikon High ISO Noise (Dark Sky)
SONY vs NIKON HIGH ISO under DARK SKIES
Noise levels appeared visually similar but the Sony showed more shadow details. Excellent!

I did put all the high ISO images through the classic noise reduction program Noise Ninja to measure total Luminance and Chrominance noise, and included the Canon 6D MkII’s images.

The resulting values and graph show the Sony actually measured worse for noise than the Nikon at each high ISO speed, 3200 to 12800, though with both performing much better than the Canon.

The higher noise of the Canon is visually obvious, but I’d say the Sony a7III and Nikon D750 are pretty equal visually for noise, despite the numbers.

Noise Ninja Value Graph
COMPARING NOISE WITH NOISE NINJA

DARK SKY ISO INVARIANCY

Again, here I show only the Sony and Nikon, the two “ISO invariant” cameras. The correct exposure for the scene was 30 seconds at ISO 6400 and f/2. The images shown here were shot at lower ISOs to underexposure the dark scene by 2 to 4 stops or EV. Those underexposed images were then boosted later in processing (in Adobe Camera Raw) by the required Exposure Value to equalize the image brightness.

Contrary to expectations, the Sony did not show any great loss in image quality as it crossed the ISO 640 boundary into its lower ISO range. But the Nikon did show more image artifacts in the “odd-numbered” ISOs of 640 and 500. In this test, the Nikon did not perform as well as the Sony for ISO invariancy. Go figure!

Again, the differences are in images vastly underexposed. And both cameras performed much better than the ISO “variant” Canon in this test.

Sony vs Nikon ISO Invariancy (Dark Sky)
DARK SKY ISO INVARIANCY
Here the Sony a7III performed well and better than the Nikon D750.

STAR EATER REVISITED

I shot images over a wide-range of exposures, from 2 seconds to 2 minutes, but show only the ones covering the 2-second to 4-second range, where the “star-eater” anti-aliasing or noise smoothing applied by Sony kicks in (above 3.2 seconds it seems).

I shot with the Sony a7III on Single shot drive mode, on Continuous Low drive mode (with the camera controlling the shutter speed in both cases), and a set with the Sony on Bulb and the shutter speed set by an external Vello intervalometer.

This is really pixel peeping at 400%. In Single drive mode, stars and noise soften ever so slightly at 4 seconds and higher. In Continuous mode, I think the effect is still there but maybe a little less. In shots on Bulb controlled by the External Timer, maybe the stars at 4 seconds are a little sharper still. But this is a tough call. To me, the star eater effect on the Sony a7III is a non-issue. It may be more serious on other Sony alphas.

Sony Star Eater-Shutter Control Series
STAR EATING vs DRIVE MODE
This series shows star sharpness in images taken in Single and Continuous drive modes, and in Externally Timed exposures.

DE-BAYERING STAR ARTIFACTS

An issue that, to me, has a more serious effect on star quality is the propensity of the Sony, and to some extent the Nikon, to render tiny stars as brightly colored points, unrealistically so. In particular, many stars look green, from the dominance of green-filtered photosites on Bayer-array sensors.

Here I compare all three cameras for this effect in two-minute tracked exposures taken with Long Exposure Noise Reduction (i.e. in-camera dark frame subtraction) off and on.

The Sony shows a lot of green stars with or without LENR. The Nikon seems to discolor stars only when LENR is applied. Why would that be? The Canon is free of any such issue – stars are naturally colored whether LENR dark frames are applied or not.

This is all with Raws developed with Adobe Camera Raw.

When opening the same Raws in other programs (ON1 Photo RAW, Affinity Photo, DxO PhotoLab, and Raw Therapee) the results can be quite different, with stars often rendered with fringes of hot, colored pixels. Or rendered with little or no color at all. Raw Therapee offers a choice of de-Bayering, or “de-mosaic,” routines, and each produces different looking stars, and none look great! Certainly not as good as the Canon rendered with Camera Raw.

What’s going on here is a mystery – it’s a combination of the cameras’ unique Raw file formats and the de-Bayering routines of all the many Raw developers wrestling with the task of rendering stars that occupy only a few pixels. It’s unfair to blame just the hardware or the software.

But this test re-emphasized my thoughts that Canon DSLRs remain the best for long-exposure deep-sky imaging where you can give images as much exposure time as they need, while the ISO invariant Sony and Nikons exceed at nightscape shooting where exposures are often limited and plagued by dark shadows and noise.

Sony vs Nikon vs Canon-LENR Off and On
COLORED STARS COMPARISON
The Sony shows a propensity to render small stars in many vivid and unreal colors. The Nikon can do so after LENR is applied. The Canon is more neutral and natural.

So the pixel-peeping continues!

I hope you found these latest tests of interest.

— Alan, May 31, 2018 / Revised June 6, 2018 / © 2018 Alan Dyer / AmazingSky.com

Testing 10 Photoshop Contenders


1-Comparing Raw Developers (Wide)

To Adobe or not to Adobe. That is the question many photographers are asking with the spate of new image processing programs vying to “kill Photoshop.”

I tested more than ten contenders as alternatives to Adobe’s image processing software, evaluating them ONLY for the specialized task of editing demanding nightscape images taken under the Milky Way, both for single still images and for time-lapses of the moving sky. I did not test these programs for other more “normal” types of images.

Also, please keep in mind, I am a Mac user and tested only programs available for MacOS, though many are also available for Windows. I’ve indicated these.

But I did not test any Windows-only programs. So sorry, fans of Paintshop Pro (though see my note at the end), Photoline, Picture Window Pro, or Xara Photo & Graphic Designer. They’re not here. Even so, I think you will find there’s plenty to pick from!

This review expands upon and updates mini-reviews I included in my Nightscapes and Time-Lapses eBook, shown at right.

If you are hoping there’s a clear winner in the battle against Adobe, one program I can say does it all and for less cost and commitment, I didn’t find one.

Group of 9 (small)

However, a number of contenders offer excellent features and might replace at least one member of Adobe’s image processing suite.


For example, only four of these programs can truly serve as a layer-based editing program replacing Photoshop.

The others are better described as Adobe Lightroom competitors – programs that can catalog image libraries and develop raw image files, with some offering adjustment layers for correcting color, contrast, etc. But as with Lightroom, layering of images – to stack, composite, and mask them – is beyond their ability.

For processing time-lapse sequences, however, we don’t need, nor can we use, the ability to layer and mask several images into one composite.

What we need for time-lapses is to:

  • Develop a single key raw file, then …
  • Copy its settings to the hundreds of other raw files in the time-lapse set, then …
  • Export that folder of raw images to “intermediate JPGs” for assembly into a movie.

Even so, not all these contenders are up to the task.

Here are the image processing programs I looked at. Costs are in U.S. dollars. Most have free trial copies available.


Photoshop+Bridge+Lightroom (small)

The Champion from Adobe

Adobe Camera Raw (ACR), Photoshop, Bridge, and Lightroom, the standards to measure others by

Cost: $10 a month by subscription, includes ACR, Photoshop, Bridge, and Lightroom

Website: https://www.adobe.com

OS: Windows and Mac

Adobe Camera Raw (ACR) is the raw development plug-in that comes with Photoshop and Adobe Bridge, Adobe’s image browsing application that accompanies Photoshop. Camera Raw is equivalent to the Develop module in Lightroom, Adobe’s cataloguing and raw processing software. Camera Raw and Lightroom have identical processing functions and can produce identical results.

Photoshop and Lightroom complement each other and are now available together, but only by monthly subscription through Adobe’s Creative Cloud service, at $10/month. Though $120 for a year is not far off the cost of purchasing many of these other programs and perhaps upgrading them annually, many photographers prefer to purchase their software and not subscribe to it.

Thus the popularity of these alternative programs. Most offered major updates in late 2017.

My question is, how well do they work? Are any serious contenders to replace Photoshop or Lightroom?


Group of 5 Raw DevelopersLightroom Contenders: Five Raw Developers

ACDSee Photo Studio (current as of late 2017)

Cost: $60 to $100, depending on version, upgrades $40 to $60.

Website: http://www.acdsystems.com

OS: Windows and Mac

I tested the single MacOS version. Windows users have a choice of either a Standard or Professional version. Only the Pro version offers the full suite of raw development features, in addition to cataloging functions. The MacOS version resembles the Windows Pro version.


Capture One v11 (late 2017 release)

Cost: $299, and $120 for major upgrades, or by subscription for $180/year

Website: https://www.phaseone.com

OS: Windows and Mac

As of version 11 this powerful raw developer and cataloguing program offers “Layers.” But these are only for applying local adjustments to masked areas of an image. You cannot layer different images. So Capture One cannot be used like Photoshop, to stack and composite images. It is a Lightroom replacement only, but a very good one indeed.


Corel Aftershot Pro v3 (late 2017)

Cost: $80, and $60 for upgrades

Website: http://www.aftershotpro.com/en/

OS: Windows, Mac, and Linux

Here’s a low cost Lightroom replacement for image management and raw processing abilities. Noise reduction is “Perfectly Clear” from Athentech and works well.


DxO PhotoLab ELITE v1 (late 2017)

Cost: $199

Website: http://www.dxo.com/us/photography/photo-software/dxo-photolab

OS: Windows and Mac

The ELITE version of what DxO now calls “PhotoLab” offers DxO’s superb PRIME noise reduction and excellent ClearView contrast enhancement feature. While it has an image browser, PhotoLab does not create a catalog, so this isn’t a full Lightroom replacement, but it is a superb raw developer. DxO also recently acquired the excellent Nik Collection of image processing plug-ins, so we can expect some interesting additions and features.


Raw Therapee v5.3 (mid-2017 release)

Cost: Free

Website: http://rawtherapee.com

OS: Windows, Mac, and Linux

This free open source program has been created and is supported by a loyal community of programmers. It offers a bewildering blizzard of panels and controls, among them the ability to apply dark frames and flat field images, features unique among any raw developer and aimed specifically at astrophotographers. Yes, it’s free, but the learning curve is precipitous.


Group of 4 Layer-Based EditorsPhotoshop Contenders: Four Raw Developers with Layering/Compositing

These programs can not only develop at least single raw images, if not many, but also offer some degree of image layering, compositing, and masking like Photoshop.

However, only ON1 Photo RAW can do that and also catalog/browse images as Lightroom can. Neither Affinity, Luminar, or Pixelmator offer a library catalog like Lightroom, nor even a file browsing function such as Adobe Bridge, serious deficiencies I feel.


Affinity Photo v1.6 (late 2017)

Cost: $50

Website: https://affinity.serif.com

OS: Windows and Mac

This is the lowest cost raw developer and layer-based program on offer here, and has some impressive features, such as stacking images, HDR blending, and panorama stitching. However, it lacks any library or cataloguing function, so this is not a Lightroom replacement, but it could replace Photoshop.


Luminar 2018

Cost: $80, and $40 for major upgrades

Website: https://macphun.com

OS: Windows and Mac

Macphun has changed their name to Skylum and now makes their fine Luminar program for both Mac and Windows. While adding special effects is its forte, Luminar does work well both as a raw developer and layer-based editor. But like Affinity, it has no cataloguing feature. It cannot replace Lightroom.


ON1 Photo RAW 2018

Cost: $120, and $100 for major upgrades

Website: https://www.on1.com

OS: Windows and Mac

Of all the contenders tested here, this is the only program that can truly replace both Lightroom and Photoshop, in that ON1 has cataloguing, raw developing, and image layering and masking abilities. In fact, ON1 allows you to migrate your Lightroom catalog into its format. However, ON1’s cost to buy and maintain is similar to Adobe’s Creative Cloud Photo subscription plan. It’s just that ON1’s license is “perpetual.”

NOTE: Windows users might find Corel’s Paintshop Pro 2018 a good “do-it-all” solution – I tested only Corel’s raw developer program Aftershot Pro, which Paintshop Pro uses.


Pixelmator Pro v1 (late 2017 release)

Cost: $60

Website: http://www.pixelmator.com/pro/

OS: MacOS only

The “Pro” version of Pixelmator was introduced in November 2017. It has an innovative interface and many fine features, and it allows layering and masking of multiple images. However, it lacks some of the key functions (listed below) needed for nightscape and time-lapse work. Touted as a Photoshop replacement, it isn’t there yet.


The Challenge

This is the image I threw at all the programs, a 2-minute exposure of the Milky Way taken at Writing-on-Stone Provincial Park in southern Alberta in late July 2017.

NOTE: Click/tap on any of the screen shots to bring them up full screen so you can inspect and save them. 

2-ACR Original Undeveloped
Original Raw Image Out of the Camera, BEFORE Development

The lens was the Sigma 20mm Art lens at f/2 and the camera the Nikon D750 at ISO 1600.

The camera was on a tracking unit (a Sky-Watcher Star Adventurer Mini) to keep stars pinpoints.

Thus the ground is blurred. Keep that in mind, as it will always look fuzzy in the comparison images. But it does show up noise well, including hot pixels. This image of the sky is designed to be composited with one taken without the tracker turning, to keep the ground sharp.

3-ACR Developed (Wide)
Raw Image AFTER Development in Adobe Camera Raw

Above is the image after development in Adobe Camera Raw (ACR), using sliders under its Basic, Tone Curve, Detail, HSL, Lens Corrections, and Effects tabs. Plus I added a “local adjustment” gradient to darken the sky at the top of the frame. I judged programs on how well they could match or beat this result.

4-Adobe Lightroom
Same Image Developed in Adobe Lightroom

Above is the same image developed in Adobe Lightroom, to demonstrate how it can achieve identical results to Camera Raw, because at heart it is Camera Raw.


Feature Focus

I have assumed a workflow that starts with raw image files from the camera, not JPGs, for high-quality results.

And I have assumed the goal of making that raw image look as good as possible at the raw stage, before it goes to Photoshop or some other bit-mapped editor. That’s an essential workflow for time-lapse shooting, if not still-image nightscapes.

However, I made no attempt to evaluate all these programs for a wide range of photo applications. That would be a monumental task!

Nor, in the few programs capable of the task, did I test image layering. My focus was on developing a raw image. As such, I did not test the popular free program GIMP, as it does not open raw files. GIMP users must turn to one of the raw developers here as a first stage.

If you are curious how a program might perform for your purposes and on your photos, then why not test drive a trial copy?

Instead, my focus was on these programs’ abilities to produce great looking results when processing one type of image: my typical Milky Way nightscape, below.

TIFF from DxO into Photoshop
TIFF Exported from DxO PhotoLab … then Imported into Photoshop

Such an image is a challenge because…

  • The subject is inherently low in contrast, with the sky often much brighter than the ground. The sky needs much more contrast applied, but without blocking up the shadows in the ground.
  • The sky is often plagued by off-color tints from artificial and natural sky glows.
  • The ground is dark, perhaps lit only by starlight. Bringing out landscape details requires excellent shadow recovery.
  • Key to success is superb noise reduction. Images are shot at high ISOs and are rife with noise in the shadows. We need to reduce noise without losing stars or sharpness in the landscape.

I focused on being able to make one image look as good as possible as a raw file, before bringing it into Photoshop or a layer-based editor – though that’s where it will usually end up, for stacking and compositing, as per the final result shown at the end.

I then looked at each program’s ability to transfer that one key image’s settings over to what could be hundreds of other images taken that night, either for stacking into star trails or for assembling into a time-lapse movie.


Summary Conclusions

1-Comparing Raw Developers (Wide)
Results of 8 Programs compared to ACR (at left)

None of the programs I tested ticked all the boxes in providing all the functions and image quality of the Adobe products.

But here’s a summary of my recommendations:


For Advanced Time-Lapse

Photoshop+Bridge+Lightroom+LRT

None of the non-Adobe programs will work with the third-party software LRTimelapse (www.lrtimelapse.com). It is an essential tool for advanced time-lapse processing. LRTimelapse works with Lightroom or ACR/Bridge to gradually shift processing settings over a sequence, and smooth annoying image flickering.

If serious and professional time-lapse shooting is your goal, none of the Adobe contenders will work. Period. Subscribe to Creative Cloud. And buy LRTimelapse.


For Basic Time-Lapse

Group of 5 for Time-Lapse

However, for less-demanding time-lapse shooting, when the same settings can be applied to all the images in a sequence, then I feel the best non-Adobe choices are, in alphabetical order:

  • ACDSee
  • Capture One
  • Corel Aftershot Pro
  • DxO PhotoLab
  • ON1 Photo RAW

… With, in my opinion, DxO and Capture One having the edge for image quality and features. But all five have a Library or Browser mode with easy-to-use Copy & Paste and Batch Export functions needed for time-lapse preparation.

Also worth a try is PhotoDirector9 (MacOS and Windows), a good Lightroom replacement. Scroll to the end for more details and a link.


For Still Image Nightscapes

Group of 3 for Still Images

If you are processing just individual still images, perhaps needing only to stack or composite a few exposures, and want to do all the raw development and subsequent layering of images within one non-Adobe program, then look at (again alphabetically):

  • Affinity Photo
  • Luminar 2018
  • ON1 Photo RAW 2018

… With Affinity Photo having the edge in offering a readily-available function off its File menu for stacking images, either for noise smoothing (Mean) or creating star trails (Maximum).

However, I found its raw development module did not produce as good a result as most competitors due to Affinity’s poorer noise reduction and less effective shadow and highlight controls. Using Affinity’s “Develop Persona” module, I could not make my test image look as good as with other programs.

Luminar 2018 has better noise reduction but it demands more manual work to stack and blend images.

While ON1 Photo Raw has some fine features and good masking tools, it exhibits odd de-Bayering artifacts, giving images a cross-hatched appearance at the pixel-peeping level. Sky backgrounds just aren’t smooth, even after noise reduction.

To go into more detail, these are the key factors I used to compare programs.


Noise Reduction

Absolutely essential is effective noise reduction, of luminance noise and chrominance color speckles and splotches.

Ideally, programs should also have a function for suppressing bright “hot” pixels and dark “dead” pixels.

Here’s what I consider to be the “gold standard” for noise reduction, Adobe Camera Raw’s result using the latest processing engine in ACR v10/Photoshop CC 2018.

5A-ACR (Close-Up)
BEFORE and AFTER Noise Reduction with Adobe Camera Raw (ACR)

I judged other programs on their ability to produce results as good as this, if not better, using their noise reduction sliders. Some programs did better than others in providing smooth, noiseless skies and ground, while retaining detail.

5B-DxO Noise Reduction
BEFORE and AFTER Noise Reduction and Other Adjustments with DxO PhotoLab

For example, one of the best was DxO PhotoLab, above. It has excellent options for reducing noise without being overwhelming in its choices, the case with a couple of other programs. For example, DxO has a mostly effective dead/hot pixel removal slider.

ACR does apply such a hot pixel removal “under the hood” as a default, but often still leaves many glaring hot specks that must be fixed later in Photoshop.

Comparing Noise Reduction

6-Comparing Raw Developers (CU)
300% Close-Ups to Compare Noise Reduction

Above are 8 of the contender programs compared to Camera Raw for noise reduction.

Missing from this group is the brand new Pixelmator Pro, for MacOS only. It does not yet have any noise reduction in its v1 release, a serious deficiency in imaging software marketed as “Pro.” For that reason alone, I cannot recommend it. I describe its other deficiencies below.


Lens Corrections

The wide-angle lenses we typically use in nightscape and time-lapse imaging suffer from vignetting and lens distortions. Having software that can automatically detect the lens used and apply bespoke corrections is wonderful.

8B-Capture One Lens Correction
Lens Corrections in Capture One

Only a few programs, such as Capture One (above), have a library of camera and lens data to draw upon to apply accurate corrections with one click. With others you have to dial in corrections manually by eye, which is crude and inaccurate.


Shadows and Highlights

All programs have exposure and contrast adjustments, but the key to making a Milky Way nightscape look good is being able to boost the shadows (the dark ground) while preventing the sky from becoming overly bright, yet while still applying good contrast to the sky.

7-DxO Shadows and Highlights
Shadows and Highlight and other Enhancements in DxO PhotoLab

Of the contenders, I liked DxO PhotoLab best (shown above), not only for its good shadow and highlight recovery, but also excellent “Smart Lighting” and “ClearView” functions which served as effective clarity and dehaze controls to snap up the otherwise low-contrast sky. With most other programs it was tough to boost the shadows without also flattening the contrast.

On the other hand, Capture One’s excellent layering and local adjustments did make it easier to brush in adjustments just to the sky or ground.

However, any local adjustments like those will be feasible only for still images or time-lapses where the camera does not move. In any motion control sequences the horizon will be shifting from frame to frame, making precise masking impractical over a sequence of hundreds of images.

Therefore, I didn’t place too much weight on the presence of good local adjustments. But they are nice to have. Capture One, DxO PhotoLab, and ON1 win here.


Selective Color Adjustments

All programs allow tweaking the white balance and overall tint.

But it’s beneficial to also adjust individual colors selectively, to enhance red nebulas, enhance or suppress green airglow, bring out green grass, or suppress yellow or orange light pollution.

Some programs have an HSL panel (Hue, Saturation, Lightness) or an equalizer-style control for boosting or dialing back specific colors.

8A-Capture One Color Adjustments
Color Adjustments in Capture One

Capture One (above) has the most control over color correction, with an impressive array of color wheels and sliders that can be set to tweak a broad or narrow range of colors.

And yet, despite this, I was still unable to make my test image look quite the way I wanted for color balance. ACR and DxO PhotoLab still won out for the best looking final result.


Copy and Paste Settings

Even when shooting nightscape stills we often take several images to stack later. It’s desirable to be able to process just one image, then copy and paste its settings to all the others in one fell swoop. And then to be able to inspect those images in thumbnails to be sure they all look good.

Some programs (Affinity Photo, Luminar, Pixelmator Pro) lack any library function for viewing or browsing a folder of thumbnail images. Yes, you can export a bunch of images with your settings applied as a user preset, but that’s not nearly as good as actually seeing those images displayed in a Browser mode.

9A-ON1 Photo RAW Copy & Paste
Copy and Paste Settings in ON1 Photo RAW

What’s ideal is a function such as ON1 Photo RAW displays here, and that some other programs have: the ability to inspect a folder of images, work on one, then copy and paste its settings to all the others in the set.

This is absolutely essential for time-lapse work, and nice to have even when working on a small set to be stacked into a still image.


Batch Export

Once you develop a folder of raw images with “Copy and Paste,” you now have to export them with all those settings “baked into” the exported files.

This step is to create an intermediate set of JPGs to assemble into a movie. Or perhaps to stack into a star trail composite using third party software such as StarStaX, or to work on the images in another layer-based program of your choice.

9B-ON1 Photo RAW Batch Export
Batch Export in ON1 Photo RAW

As ON1 Photo RAW shows above, this is best done using a Library or Browser mode to visually select the images, then call up an Export panel or menu to choose the image size, format, quality, and location for the exports.

Click Export and go for coffee – or a leisurely dinner – while the program works through your folder. All programs took an hour or more to export hundreds of images.


Design

Those functions were the key features I looked for when evaluating the programs for nightscape and time-lapse work.

Every program had other attractive features, often ones I wished were in Adobe Camera Raw. But if the program lacked any of the above features, I judged it unsuitable.

Yes, the new contenders to the Photoshop crown have the benefit of starting from a blank slate for interface design.

26-Luminar Interface
Luminar 2018’s Clean User Interface

Many, such as Luminar 2018 above, have a clean, attractive design, with less reliance on menus than Photoshop.

Photoshop has grown haphazardly over 25 years, resulting in complex menus. Just finding key functions can take many tutorial courses!

But Adobe dares to “improve” Photoshop’s design and menu structure at its peril, as Photoshop fans would scream if any menus they know and love were to be reorganized!

The new mobile-oriented Lightroom CC is Adobe’s chance to start afresh with a new interface.


Summary Table of Key Features

Comparison Table
Click or tap to view and save full screen version.

Fair = Feature is present but doesn’t work as easily or produce as good a result

Partial = Program has lens correction but failed to fully apply settings automatically / DxO has a Browse function but not Cataloging

Manual = Program has only a manually-applied lens correction

= Program is missing that feature altogether


Program-by-Program Results

Group of 9 (small)

I could end the review here, but I feel it’s important to present the evidence, in the form of screen shots of all the programs, showing both the whole image, and a close-up to show the all-important noise reduction.


ACDSee Photo Studio

10A-ACDSee (Wide)
ACDSee Full Screen
10B-ACDSee (CU)
ACDSee Enlargement

PROS: This capable cataloging program has good selective color and highlight/shadow recovery, and pretty smooth noise reduction. It can copy and paste settings and batch export images, for time-lapses. It is certainly affordable, making it a low-cost Lightroom contender.

CONS: It lacks any gradient or local adjustments, or even spot removal brushes. Lens corrections are just manual. There is no dehaze control, which can be useful for snapping up even clear night skies. You cannot layer images to create composites or image stacks. This is not a Photoshop replacement.


Affinity Photo

11A-Affinity Photo (Wide)
Affinity Photo Full Screen
11B-Affinity Photo (CU)
Affinity Photo Enlargement

PROS: Affinity supports image layers, masking with precise selection tools, non-destructive “live” filters (like Photoshop’s Smart Filters), and many other Photoshop-like functions. It has a command for image stacking with a choice of stack modes for averaging and adding images.

It’s a very powerful but low cost alternative to Photoshop, but not Lightroom. It works fine when restricted to working on just a handful of images.

CONS: Affinity has no lens correction database, and I found it hard to snap up contrast in the sky and ground without washing them out, or having them block up. Raw noise reduction was acceptable but not up to the best for smoothness. It produced a blocky appearance. There are no selective color adjustments.

Nor is there any library or browse function. You can batch export images, but only through an unfriendly dialog box that lists images only by file name – you cannot see them. Nor can you copy and paste settings visually, but only apply a user-defined “macro” to develop images en masse upon export.

This is not a program for time-lapse work.


Capture One 11

13A-Capture One Pro (Wide)
Capture One 11 Full Screen
13B-Capture One Pro (CU)
Capture One 11 Enlargement

PROS: With version 11 Capture One became one of the most powerful raw developers, using multiple layers to allow brushing in local adjustments, a far better method than Adobe Camera Raw’s local adjustment “pins.” It can create a catalog from imported images, or images can be opened directly for quick editing. Its noise reduction was good, with hot pixel removal lacking in Camera Raw.

Its color correction options were many!

It can batch export images. And it can export files in the raw DNG format, though in tests only Adobe Camera Raw was able to read the DNG file with settings more or less intact.

CONS: It’s costly to purchase, and more expensive than Creative Cloud to subscribe to. Despite all its options I could never quite get as good looking an image using Capture One, compared to DxO PhotoLab for example.

It is just a Lightroom replacement; it can’t layer images.


Corel Aftershot Pro 3

12A-Aftershot Pro (Wide)
Corel Aftershot Pro Full Screen
12B-Aftershot Pro (CU)
Corel Aftershot Pro Enlargement

PROS: This low-cost option has good noise reduction using Athentech’s Perfectly Clear process, with good hot pixel or “impulse” noise removal. It has good selective color and offers adjustment layers for brushing in local corrections. And its library mode can be used to copy and paste settings and batch export images.

Again, it’s solely a Lightroom alternative.

CONS: While it has a database of lenses, and identified my lens, it failed to apply any automatic corrections. Its shadow and highlight recovery never produced a satisfactory image with good contrast. Its local adjustment brush is very basic, with no edge detection.


DxO PhotoLab

14A-DxO PhotoLab (Wide)
DxO PhotoLab Full Screen
14B-DxO PhotoLab (CU)
DxO PhotoLab Enlargement

PROS: I found DxO produced the best looking image, better perhaps than Camera Raw, because of its DxO ClearView and Smart Lighting options. It has downloadable camera and lens modules for automatic lens corrections. Its noise reduction was excellent, with its PRIME option producing by far the best results of all the programs, better perhaps than Camera Raw, plus with hot pixel suppression.

DxO has good selective color adjustments, and its copy and paste and batch export work fine.

CONS: There are no adjustment layers as such. Local adjustments and repairing are done through the unique U-Point interface which works something like ACR’s “pins,” but isn’t as visually intuitive as masks and layers. Plus, DxO is just a raw developer; there is no image layering or compositing. Nor does it create a catalog as such.

So it is not a full replacement for either Lightroom or Photoshop. But it does produce great looking raw files for export (even as raw DNGs) to other programs.


Luminar 2018

15A-Luminar 2018 (Wide)
Luminar 2018 Full Screen
15B-Luminar 2018 (CU)
Luminar 2018 Enlargement

PROS: Luminar has good selective color adjustments, a dehaze control, and good contrast adjustments for highlights, mid-tones, and shadows. Adjustments can be added in layers, making them easier to edit. Noise reduction was smooth and artifact-free, but adjustments were basic. Many filters can be painted on locally with a brush, or with a radial or gradient mask.

CONS: It has no lens correction database; all adjustments are manual. The preview was slow to refresh and display results when adjusting filters. The interface is clean but always requires adding filters to the filter panel to use them when creating new layers. Its batch export is crude, with only a dialog box and no visual browser to inspect or select images.

Settings are applied as a user preset on export, not through a visual copy-and-paste function. I don’t consider that method practical for time-lapses.


ON1 Photo RAW 2018

16A-ON1 Photo Raw (Wide)
ON1 Photo RAW Full Screen
16B-ON1 Photo Raw (CU)
ON1 Photo RAW Enlargement

PROS: ON1 is the only program of the bunch that can: catalog images, develop raw files, and then layer and stack images, performing all that Lightroom and Photoshop can do. It is fast to render previews in its “Fast” mode, but in its “Accurate” mode ON1 is no faster than Lightroom. It has good layering and masking functions, both in its Develop mode and in its Photoshop-like Layers mode.

Selective color and contrast adjustments were good, as was noise reduction. Developing, then exporting a time-lapse set worked very well, but still took as long as with Lightroom or Photoshop.

CONS: Despite promising automatic lens detection and correction, ON1 failed to apply any vignetting correction for my 20mm Sigma lens. Stars exhibited dark haloes, even with no sharpening, dehaze, or noise reduction applied. Its de-Bayering algorithm produced a cross-hatched pattern at the pixel level, an effect not seen on other programs.

Noise reduction did not smooth this. Thus, image quality simply wasn’t as good.


Pixelmator Pro

17A-Pixelmator Pro (Wide)
Pixelmator Pro Full Screen
17B-Pixelmator Pro (CU)
Pixelmator Pro Enlargement

PROS: It is low cost. And it has an attractive interface.

CONS: As of version 1 released in November 2017 Pixelmator Pro lacks: any noise reduction (it’s on their list to add!), any library mode or copy and paste function, nor even the ability to open several images at once displayed together.

It is simply not a contender for “Photoshop killer” for any photo application, despite what click-bait “reviews” promise, ones that only re-write press releases and don’t actually test the product.


Raw Therapee v5.3

18A-Raw Therapee (Wide)
Raw Therapee Full Screen
18B-Raw Therapee (CU)
Raw Therapee Enlargement – With and Without Noise Reduction

PROS: It’s free! It offers an immense number of controls and sliders. You can even change the debayering method. It detects and applies lens corrections (though in my case only distortion, not vignetting). It has good selective color with equalizer-style sliders. It has acceptable (sort of!) noise reduction and sharpening with a choice of methods, and with hot and dead pixel removal.

It can load and apply dark frames and flat fields, the only raw developer software that can. This is immensely useful for deep-sky photography.

CONS: It offers an immense number of controls and sliders! Too many! It is open source software by committee, with no one in charge of design or user friendliness. Yes, there is documentation, but it, too, is a lot to wade through to understand, especially with its broken English translations. This is software for digital signal processing geeks.

But worst of all, as shown above, its noise reduction left lots of noisy patches in shadows, no matter what combination of settings I applied. Despite all its hundreds of sliders, results just didn’t look as good.


What About …? (updated December 28)

What About Group of 8

No matter how many programs I found to test, someone always asks, “What about …?” In some cases such comments pointed me to programs I wasn’t even aware of, but subsequently tried out. So here are even more to pick from…


Acorn (https://flyingmeat.com/acorn/)

Acorn
Acorn’s very basic raw adjustment module.

Billed as having “everything you need in an image editor,” this low-cost ($30) MacOS-only program is anything but. Its raw developer module is crude and lacks any of the sophisticated range of adjustments offered by all the other programs on offer here. It might be useful as a layer-based editor of images developed by another program.


Alien Skin Exposure x3 (https://www.alienskin.com)

Alien Skin (Wide)
Alien Skin Exposure x3 at work on the the image

Available for Mac and Windows for $150, this Lightroom competitor offers a good browser function, with the ability to “copy-from-one and paste-to-many” images (unlike some of the programs below), and a good batch export function for time-lapse work. It has good selective color controls and very good noise reduction providing a smooth background without artifacts like blockiness or haloes. Local adjustments, either through brushed-on adjustments or through gradients, are applied via handy and easy to understand (I think!) layers.

While it has auto lens corrections, its database seemed limited — it did not have my Sigma 20mm lens despite it being on the market for 18 months. Manual vignetting correction produced a poor result with just a washed out look.

The main issue was that its shadow, highlight, and clarity adjustments just did not produce the snap and contrast I was looking for, but that other programs could add to raw files. Still, it looks promising, and is worth a try with the trial copy. You might find you like it. I did not. For similar cost, other programs did a better job, notably DxO PhotoLab.


darktable (http://www.darktable.org)

In the same ilk as Raw Therapee, I also tested out another free, open-source raw developer, one simply called “darktable,” with v2.2.5 shown below. While it has some nice functions and produced a decent result, it took a lot of time and work to use.

19A-Darktable
darktable RAW Developer

The MacOS version I tried (on a brand new 5K iMac) ran so sluggishly, taking so long to re-render screen previews, that I judged it impractical to use. Sliders were slow to move and when I made any adjustments often many seconds would pass before I would see the result. Pretty frustrating, even for free.


Iridient Developer (http://www.iridientdigital.com)

19B-Iridient Developer
Iridient Developer

A similar crowd-developed raw processing program, Iridient Developer (above), sells for $99 US. I tested a trial copy of v3.2. While it worked OK, I was never able to produce a great looking image with it. It had no redeeming features over the competition that made its price worthwhile.


Paintshop Pro (https://www.paintshoppro.com/en/)

PaintShop Raw Developer
Paintshop Pro’s included but very basic Raw developer.

Using Parallels running Windows 10 on my Mac, I did try out this popular Windows-only program from Corel. By itself, Paintshop Pro’s raw developer module (shown above) is basic, crude and hardly up to the tax of processing demanding raw files. You are prompted to purchase Corel’s Aftershot Pro for more capable raw development, and I would agree – Aftershot would be an essential addition. However …

As I showed above, I did test the MacOS version of Aftershot Pro on my raw sample image, and found it did the poorest job of making my raw test image look good. Keep in mind that it is the ability of all these programs to develop this typical raw nightscape image that I am primarily testing.

That said, given a well-developed raw file, Paintshop Pro can do much more with it, such as further layering of images and applying non-destructive and masked adjustment layers, as per Photoshop. Indeed, it is sold as a low-cost (~ $60) Photoshop replacement. As such, many Windows users find Paintshop’s features very attractive. However, Paintshop lacks the non-destructive “smart” filters, and the more advanced selection and masking options offered by Photoshop, Affinity Photo, and ON1 Photo Raw. If you have never used these, you likely don’t realize what you are missing.

If it’s an Adobe alternative you are after, I would suggest Windows users would be better served by other options. Why not test drive Affinity and ON1?


PhotoDirector 9 (https://www.cyberlink.com/products/photodirector-ultra/features_en_US.html

Photo Director Wide
PhotoDirector’s very Lightroom-like interface and controls.

This was a surprising find. Little known, certainly to me, this Windows and MacOS program from the Taiwanese company Cyberlink, is best described as a Lightroom substitute, but it’s a good one. Its regular list price is $170. I bought it on sale for $60.

Like Lightroom, working on any images with PhotoDirector requires importing them into a catalog. You cannot just browse to the images. Fine. But one thing some people complain about with Lightroom is the need to always import images.

I was impressed with how good a job PhotoDirector did on my raw test image. PhotoDirector has excellent controls for shadow and highlight recovery, HSL selective color, copying-and-pasting settings, and batch exporting. So it will work well for basic time-lapse processing.

Noise reduction was very good and artifact-free. While it does have automatic lens corrections, its database did not include the 2-year old Sigma 20mm Art lens I used. So it appears its lens data is not updated frequently.

PhotoDirector has good local adjustments and gradients using “pins” rather than layers, similar to Camera Raw and Lightroom.

After performing raw image “Adjustments,” you can take an image into an Edit module (for adding special effects), then into a Layers module for further work. However, doing so destructively “flattens” the image to apply the raw adjustments you made. You cannot go back and tweak the raw settings in the Adjustment module, as you can when opening a raw file as a “smart object” in Adobe Photoshop.

While PhotoDirector does allow you to layer in other images to make basic composites (such as adding type or logos), there is no masking function nor any non-destructive adjustment layers. So this is most assuredly not a Photoshop substitute, despite what the advertising might suggest. But if it’s a Lightroom replacement you are after, do check it out in a trial copy.


Picktorial v3 (https://www.picktorial.com)

Picktorial
MacOS-only Picktorial v3, with its clean interface

This little-known MacOS-only program (only $40 on sale) for developing raw images looks very attractive, with good selective color, lots of local adjustments, and good masking tools, the features promoted on the website. It does have a browse function and can batch export a set of developed files.

However … its noise reduction was poor, introducing glowing haloes around stars when turned up to any useful level. Its shadows, highlights, and contrast adjustments were also poor – it was tough to make the test image look good without flattening contrast or blocking up shadows. Boosting clarity even a little added awful dark haloes to stars, making this a useless function. It has no lens correction, either automatic or manual. Like Topaz Studio, below, it cannot copy and paste settings to a batch of images, only to one image at a time, so it isn’t useful for time-lapse processing.

I cannot recommend this program, no matter how affordable it might be.


Silky Pix Developer Studio 8 (http://www.silkypix.us

Silky Pix Wide

Popular among some camera manufacturers as their included raw developer, Silky Pix can be purchased separately ($80 list price for the standard version, $250 list price for the Pro version) with support for many cameras’ image files. It is available for MacOS and Windows. I tried the lower-cost “non-Pro” version 8. It did produce a good-looking end result, with good shadow and highlight recovery, and excellent color controls. Also on the plus side, Silky Pix has very good copy-and-paste functions for development settings, and good batch export functions, so it can be used to work on a folder of time-lapse frames.

On the down side, noise reduction, while acceptable, left an odd mottled pattern, hardly “silky.” The added “Neat” noise reduction option only smoothed out detail and was of little value except perhaps for very noisy images. Noise reduction did nothing to remove hot pixels, leaving lots of colored specks across the image. The program uses unorthodox controls whose purposes are not obvious. Instead of  Highlights and Shadows you get Exposure Bias and HDR. Instead of Luminance and Color noise reduction, you get sliders labeled Smoothness and Color Distortion. You really need to read the extensive documentation to learn how to use this program.

I found sliders could be sticky and not easy to adjust precisely. The MacOS version was slow, often presenting long bouts of spinning beachballs while it performed some function. This is a program worth a try, and you might find you like it. But considering what the competition offers, I would not recommend it.


Topaz Studio (http://www.topazlabs.com)

Topaz Studio (Wide)
Topaz Studio at work on the test image

While Topaz Labs previously offered only plug-ins for Photoshop and other programs (their Topaz DeNoise 6 is very good), their Topaz Studio stand-alone program now offers full raw processing abilities.

It is for Mac and Windows. While it did a decent job developing my test Milky Way image (above), with good color and contrast adjustments, it cannot copy and paste settings from one image to a folder of images, only to one other image. Nor can it batch export a folder of images. Both deficiencies make it useless for time-lapse work.

In addition, while the base program is free, adding the “Pro Adjustments” modules I needed to process my test image (Noise Reduction, Dehaze, Precision Contrast, etc.) would cost $160 – each Adjustment is bought separately. Some users might like it, but I wouldn’t recommend it.


And … Adobe Photoshop Elements v18 (late 2017 release)

What about Adobe’s own Photoshop “Lite?” Elements is available for $99 as a boxed or downloadable one-time purchase, but with annual updates costing about $50. While it offers image and adjustment layers, it cannot do much with 16-bit images, and has very limited functions for developing raw files.

And its Lightroom-like Organizer module does not have any copy-and-paste settings or batch export functions, making it unsuitable for time-lapse production.

19C-Photoshop Elements
Photoshop Elements v18 – Showing its Version of Camera Raw Lite

Elements is for processing photos for the snapshot family album. Like Apple’s Photos and other free photo apps, I don’t consider Elements to be a serious option for nightscape and time-lapse work. But it can be pressed into service for raw editing and layering single images, especially by beginners.

However, a Creative Cloud Photo subscription doesn’t cost much more than buying, then upgrading Elements outright, yet gets you far, far more in professional-level software.


And Yet More…!

In addition, for just developing raw files, you likely already have software to do the job – the program that came with your camera.

20-Canon DPP
Canon Digital Photo Professional v4

For Canon it’s Digital Photo Professional (shown above); for Nikon it’s Capture NX; for Pentax it’s Digital Camera Utility, etc.

These are all capable raw developers, but have no layering capabilities. And they read only the files from their camera brand. If theirs is the only software you have, try it. They are great for learning on.

But you’ll find that the programs from other companies offer more features and better image quality.


What Would I Buy?

Except for Capture One, which I tested as a trial copy, I did buy all the software in question, for testing for my Nightscapes eBook.

However, as I’ve described, none of the programs tick all the boxes. Each has strengths, but also weaknesses, if not outright deficiencies. I don’t feel any can fully replace Adobe products for features and image quality.

DxO to Affinity

A possible non-Adobe combination for the best image quality might be DxO PhotoLab for raw developing and basic time-lapse processing, and Affinity Photo for stacking and compositing still images, from finished TIFF files exported out of DxO and opened and layered with Affinity.

But that combo lacks any cataloging option. For that you’d have to add ACDSee or Aftershot for a budget option. It’s hardly a convenient workflow I’d want to use.

DxO vs ON1 Noise
ON1 De-Bayer Artifacts (Right) Compared to DxO PhotoLab (Left), at 400%

I’d love to recommend ON1 Photo RAW more highly as a single solution, if only it had better raw processing results, and didn’t suffer from de-Bayering artifacts (shown in a 400% close-up above, compared to DxO PhotoLab). These add the star haloes and a subtle blocky pattern to the sky, most obvious at right.


To Adobe or Not to Adobe

I’m just not anxious, as others are, to “avoid Adobe.”

I’ve been a satisfied Creative Cloud subscriber for several years, and view the monthly fee as the cost of doing business. It’s much cheaper than the annual updates that boxed Photoshop versions used to cost. Nor am I worried about Adobe suddenly jacking up the fees or holding us hostage with demands.

21-LRTimelapse
LRTimelapse at Work on a Time-Lapse Sequence

For me, the need to use LRTimelapse (shown above) for about 80 percent of all the time-lapse sequences I shoot means the question is settled. LRTimelapse works only with Adobe software, and the combination works great. Sold.

I feel Camera Raw/Lightroom produces results that others can only just match, if that.

Only DxO PhotoLab beat Adobe for its excellent contrast enhancements and PRIME noise reduction.

Yes, other programs certainly have some fine features I wish Camera Raw or Lightroom had, such as:

  • Hot and dead pixel removal
  • Dark frame subtraction and flat field division
  • Better options for contrast enhancement
  • And adding local adjustments to raw files via layers, with more precise masking tools
  • Among others!

But those aren’t “must haves.”

Using ACR or Lightroom makes it easy to export raw files for time-lapse assembly, or to open them into Photoshop for layering and compositing, usually as “smart objects” for non-destructive editing, as shown below.

21-Photoshop Final Image
Final Layered Photoshop Image

Above is the final layered image, consisting of:

  • A stack of 4 tracked exposures for the sky (the test image is one of those exposures)
  • And 4 untracked exposures for the ground.

The mean stacking smooths noise even more. The masking reveals just the sky on the tracked set. Every adjustment layer, mask, and “smart filter” is non-destructive and can be adjusted later.

I’ll work on recreating this same image with the three non-Adobe programs capable of doing so –  Affinity, Luminar, and ON1 Photo RAW – to see how well they do. But that’s the topic of a future blog.


Making the Switch?

The issue with switching from Adobe to any new program is compatibility.

While making a switch will be fine when working on all new images, reading the terabytes of old images I have processed with Adobe software (and being able to re-adjust their raw settings and layered adjustments) will always require that Adobe software.

If you let your Creative Cloud subscription lapse, as I understand it the only thing that will continue to work is Lightroom’s Library module, allowing you to review images only. You can’t do anything to them.

None of the contender programs will read Adobe’s XMP metadata files to display raw images with Adobe’s settings intact.

Conversely, nor can Adobe read the proprietary files and metadata other programs create.

ON1 Warning Dialog

With final layered Photoshop files, while some programs can read .PSD files, they usually open them just as flattened images, as ON1 warns it will do above. It flattened all of the non-destructive editing elements created in Photoshop. Luminar did the same.

23-Affinity Opening PSB File
A Layered Photoshop PSB File Opened in Affinity Photo

Only Affinity Photo (above) successfully read a complex and very large Photoshop .PSB file correctly, honouring at least its adjustment and image layers. So, if backwards compatibility with your legacy Photoshop images is important, choose Affinity Photo.

However, Affinity flattened Photoshop’s smart object image layers and their smart filters. Even Adobe’s own Photoshop Elements doesn’t honor smart objects.

Lest you think that’s a “walled garden” created by “evil Adobe,” keep in mind that the same will be true of the image formats and catalogs that all the contender programs produce.

To read the adjustments, layers, and “live filters” you create using any another program, you will need to use that program.

Will Affinity, DxO, Luminar, ON1, etc. be around in ten years?

Yes, you can save out flattened TIFFs that any program can read in the future, but that rules out using those other programs to re-work any of the image’s original settings.


In Conclusion!

24-DxO UPoint Local
U-Point Local Adjustments in DxO PhotoLab

I can see using DxO PhotoLab (above) or Raw Therapee for some specific images that benefit from their unique features.

Or using ACDSee as a handy image browser.

28-Luminar as Plug-In
Luminar 2018 as a Plug-In Within Photoshop

And ON1 and Luminar have some lovely effects that can be applied by calling them up as plug-ins from within Photoshop, and applied as smart filters. Above, I show Luminar working as a plug-in, applying its “Soft & Airy” filter.

In the case of Capture One and DxO PhotoLab, their ability to save images back as raw DNG files (the only contender programs of the bunch that can), means that any raw processing program in the future should be able to read the raw image.

27-CaptureOne DNG Opened in ACR
DNG Raw File Created by Capture One Opened in ACR

However, only Capture One’s Export to DNG option produced a raw file readable and editable by Adobe Camera Raw with its settings from Capture One (mostly) intact (as shown above).

Even so, I won’t be switching away from Adobe any time soon.

But I hope my survey has given you useful information to judge whether you should make the switch. And if so, to what program.

Thanks! 

— Alan, December 6, 2017 / © 2017 Alan Dyer / AmazingSky.com

Testing the Canon 6D Mark II for Nightscapes


Canon 6DMkII vs 6D Front

In a technical blog I compare the new Canon 6D Mark II camera with its predecessor, the Canon 6D, with the focus on performance for nightscape astrophotography.

No pretty pictures in this blog I’m afraid! This is a blog for gear geeks.

The long-awaited Canon 6D Mark II camera is out, replacing the original 6D after that camera’s popular 5-year reign as a prime choice among astrophotographers for all kinds of sky images, including nightscapes and time-lapses.

As all new cameras do, the 6D Mark II is currently fetching a full list price of $2000 U.S. Eventually it will sell for less. The original 6D, introduced in 2012 at that same list price, might still be available from many outlets, but for less, likely below $1500 US.

Shown on the left, above, the 6D Mark II is similar in size and weight to the original 6D.

However, the new Mark II offers 6240 x 4160 pixels for 26 megapixels, a bump up in resolution over the 5472 x 3648 20-megapixel 6D. The pixel pitch of the Mark II sensor is 5.7 microns vs. 6.6 microns for the 6D. 

One difference is that the port for a remote release is now on the front, but using the same solid 3-pin N3 connector as the 6D and other full-frame Canons. That makes it compatible with all external controllers for time-lapse shooting.

TESTING FOR THE NIGHT

My interest is in a camera’s performance for long-exposure astrophotography, with images taken at high ISO settings. I have no interest in auto-focus performance (we shoot at night with focus set manually), nor how well a camera works for high-speed sports shooting.

To test the Mark II against the original 6D I took test shots at the same time of a high-contrast moonlit scene in the backyard, using a range of ISO speeds typical of nightscape scenes.

The comparisons show close-ups of a scene shown in full in the smaller inset screen.

COMPARING NOISE

The key characteristic of interest for night work is noise. How well does the camera suppress the noise inherent in digital images when the signal is boosted to the high ISO settings we typically use?

6D MkII Noise at 5 ISOs
6D Mark II noise at 5 ISO speeds
This set shows the 6D MkII at five ISOs, from ISO 1600 all the way up to the seldom-used ISO 25,600, all shot in Raw, not JPG. In all cases, no noise reduction was applied in later processing, so the results do look worse than what processed images would.

Click or tap on all images to expand each image to full screen for closer inspection. 

6D Noise at 5 ISOs
6D noise at 5 ISO speeds
This set shows the same range of ISOs with the original 6D. All were taken at the same aperture, f/2.8, with a 35mm lens. Exposures were halved for each successive bump up in ISO speed, to ensure equally exposed images.

Comparing the sets, the 6D MkII shows a much greater tendency to exhibit a magenta cast in the shadows at very high ISOs, plus a lower contrast in the shadows at increasing ISOs, and slightly more luminance noise than the 6D. 

How much more noise the 6D MkII exhibits is demonstrated here.

6D MkII Noise at ISO 3200
6D MkII noise at ISO 3200 compared to 6D
To me, visually, the MkII presents about 1/2 stop, or EV, worse noise than the 6D. 

In this example, the MkII exhibits a noise level at ISO 3200 (a common nightscape setting) similar to what the 6D does if set between ISO 4000 and 5000 – about 1/2 stop worse noise.

Frankly, this is surprising. 

Yes, the MkII has a higher pixel count and therefore smaller pixels (5.7 microns in this case) that are always more prone to noise. But in the past, advances to the in-camera signal processing has prevented noise from becoming worse, despite increasing pixel count, or has even produced an improvement in noise.

For example, the 2012-vintage 6D is better for noise than Canon’s earlier 2008-era 5D MkII model by about half a stop, or EV.

After five years of camera development I would have expected a similar improvement in the 6D MkII. After all, the 6D MkII has Canon’s latest DIGIC 7 processor, vs. the older 6D’s DIGIC 5+.

Instead, not only is there no noise improvement, the performance is worse. 

That said, noise performance in the 6D MkII is still very good, and better than you’ll get with today’s 24 megapixel cropped-frame cameras with their even smaller 4 micron pixels. But the full frame 6D MkII doesn’t offer quite as much an improvement over cropped-frame cameras as does the five-year-old 6D.

ISO INVARIANCY

In the previous sets all the images were well-exposed, as best they could be for such a contrasty scene captured with a single exposure.

What happens when Raw images are underexposed, then boosted later in exposure value in processing? 

This is not an academic question, as that’s often the reality for nightscape images where the foreground remains dark. Bringing out detail in the shadows later requires a lot of Shadow Recovery or increasing the Exposure. How well will the image withstand that work on the shadows?

To test this, I shot a set of images at the same shutter speed, but at successively slower ISOs, from a well-exposed ISO 3200, to a severely underexposed ISO 100. I then boosted the Exposure setting later in Raw processing by an amount that compensated for the level of underexposure in the camera, from a setting of 0 EV at ISO 3200, to a +5 EV boost for the dark ISO 100 shots.

This tests for a camera’s “ISO Invariancy.” If a camera has a sensor and signal processing design that is ISO invariant, a boosted underexposed image at a slow ISO should look similar to a normally exposed image at a high ISO.

You’re just doing later in processing what a camera does on its own in-camera when bumping up the ISO.

But cameras that use ISO “variant” designs suffer from increased noise and artifacts when severely underexposed images are boosted later in Raw processing.

The Canon 6D and 6D MkII are such cameras.

6D MkII ISO Variancy
6D Mark II ISO Invariancy
This set above shows the results from the 6D Mark II. Boosting underexposed shadows reveals a lot of noise and a severe magenta cast.

These are all processed with Adobe Camera Raw, identical to the development engine in Adobe Lightroom.

6D ISO Variancy
6D ISO Invariancy
This set above shows the results from the 6D. The older camera, which was never great for its lack of ISO Invariancy performance, is still much better than the new Mark II. 

Underexposed shadows show less noise and discolouration in the 6D. For a comparison of the Canon 6D with the ISO Invariant Nikon D750, see my earlier Nikon vs. Canon blog from 2015. The Nikon performs much better than the 6D.

Effectively, this is the lack of dynamic range that others are reporting when testing the 6D MkII on more normal daytime images. It really rears its ugly head in nightscapes.

The lesson here is that the Mark II needs to be properly exposed as much as possible.

Don’t depend on being able to extract details later from the shadows. The adage “Expose to the Right,” which I explain at length in my Nightscapes eBook, applies in spades to the 6D MkII. 

LONG EXPOSURE NOISE REDUCTION

All the above images were taken with Long Exposure Noise Reduction (LENR) off. This is the function that, when turned on, forces the camera to take and internally subtract a dark frame – an image of just the noise – reducing thermal noise and discolouration in the shadows.

6DMkII LENR On & Off
6D Mark II LENR On and Off
Here is the 6D Mark II in a pair of  underexposed images at identical settings with LENR on and off. Not only did it not reduce noise and the magenta cast, using LENR made it worse.

This is so completely contrary to expectation that I wonder if the Mark II does not have a serious firmware issue in need of a fix in an upgrade. 

DARK FRAME BUFFER

A unique feature of Canon full-frame cameras is that when LENR is on you can take several exposures in quick succession before the dark frame kicks in and locks up the camera. This is extremely useful for deep-sky shooting.

The single dark frame then gets applied to the buffered “light frames.”

The 6D Mark II, when in either Raw or in Raw+JPG can take 3 shots in succession. This is a downgrade from the 6D which can take 4 shots when in Raw+JPG. Pity.

ADOBE CAMERA RAW vs. DIGITAL PHOTO PROFESSIONAL

My next thought was that Adobe Camera Raw, while it was reading the Mark II files fine, might not have been de-Bayering or developing them properly. So I developed the same image with both Raw developers, Adobe’s and Canon’s latest version of their own Digital Photo Professional (DPP).

ACR vs DPP-withNR
ACR vs. DPP
Here I did apply a modest and approximately similar level of noise reduction to both images:

In ACR: Color at 25, Luminosity at 40, with Sharpness at 25

In DPP: Chrominance at 8, Luminosity at 8, with Sharpness at 2

Yes, DPP did do a better job at eliminating the ugly magenta cast, but did a much worse job at reducing overall noise. DPP shows a lot of blockiness, detail loss, and artifacts left by the noise reduction.

Adobe Camera Raw and/or Lightroom remain among the best of many Raw developers.

IMAGE AVERAGING

A new feature the 6D Mark II offers is the ability to shoot and stack images in-camera. It can either “Add” the exposure values, or, most usefully, “Average” them, as shown here.

Multiple Exposure Menu
6D Mark II Multiple Exposure screen
Other newer Canon DSLRs also offer this feature, notably the 7D MkII, the 5D MkIV, the 5Ds, and even the entry-level 80D. So the 6D MkII is not unique. But the feature was not on the 6D.

Here’s the benefit.

6D MkII Averaging
6D Mark II Averaging results
The left image is a single exposure; the middle is an average stack of 4 exposures stacked in camera; the right image an average stack of 9 exposures, the maximum allowed.

Noise smooths out a lot, with less noise the more images you stack. The result is a single Raw file, not a JPG. Excellent! 

While this kind of stacking can be done later in processing in Photoshop, or in any layer-based program, many people might find this in-camera function handy.

Except, as you can see, the sky will exhibit star trails, and not as well defined as you would get from stacking them with a “Lighten” blend mode, as all star trail stacking routines use.

So this averaging method is NOT the way to do star trails. The Mark II does not offer the Brighten mode some other new Canons have that does allow for in-camera star trail stacking. Again, a pity in a camera many will choose for astrophotography.

Nevertheless, the Average mode is a handy way to create foreground landscapes with less noise, which then have to be composited later with a sky image or images.

OTHER FEATURES

On the left, below, the Mark II has a nearly identical layout of buttons and controls to the 6D on the right. So owners of the older model will feel right at home with the Mark II. That’s handy, as we astrophotographers work in the dark by feel!

Canon 6DMkII vs 6D Rear
6D Mark II (left) and 6D rear views
Of course the big new feature, a first for Canon in a full-frame camera, is the Mark II’s fully articulated screen. It flips out, tilts, and even flips around to face forward. This is super-great for all astrophotography, especially when conducted by aging photographers with aching backs!

And the screen, as with the entry-level cropped-frame Canons, is a touch screen. For someone who hasn’t used one before – me! – that’ll take some getting used to, if only in just remembering to use it.

And it remains to be seen how well it will work in the cold. But it’s great to have.

INTERVAL TIMER

Like other late-model Canon DSLRs, the 6D MkII has a built-in intervalometer. It works fine but is useable only on exposures with internally set shutter speeds up to 30 seconds.

Interval Timer Menu
6D Mark II Interval Timer screen
However, setting the Interval so it fires the shutter with a minimal gap of 1 second between shots (our usual requirement for night time-lapses) is tricky: You have to set the interval to a value not 1 second, but 2 to 3 seconds longer than the shutter speed. i.e. an exposure of 30 seconds requires an interval of 33 seconds, as shown above. Anything less and the camera misses exposures.

Why? Well, when set to 30 seconds the camera actually takes a 32-second exposure. Surprise!

Other cameras I’ve used and tested with internal intervalometers (Nikon and Pentax) behave the same way. It’s confusing, but once you are used to it, the intervalometer works fine.

Except … the manual suggests the only way to turn it off and stop a sequence is to turn off the camera. That’s crude. A reader pointed out that it is also possible to stop a time-lapse sequence by hitting the Live View Start/Stop button. However, that trick doesn’t work on sequences programmed with only a second between frames, as described above. So stopping a night time-lapse is inelegant to say the least. With Nikons you can hold down the OK button to stop a sequence, with the option then of restarting it if desired. 

Also, the internal Intervalometer cannot be used for exposures longer than 30 seconds. Again, that’s the case with all in-camera intervalometers in other models and brands.

BULB TIMER

As with many other new Canons, the Mark II has a Bulb Timer function.

Bulb Timer Menu
6D Mark II Bulb Timer screen
When on Bulb you can program in exposure times of any length. That’s a nice feature that, again, might mean an external intervalometer is not needed for many situations.

PLAYBACK SCREEN

A new feature I like is the greatly expanded information when reviewing an image.

Playback Menu-LENR Status
6D Mark II Playback screen
One of the several screens you can scroll to shows whether you have shot that image with Long Exposure Noise Reduction on or not.

Excellent! I have long wanted to see that information recorded in the metadata. Digital Photo Professional also displays that status, but not Adobe Camera Raw/Lightroom.

CONCLUSION

While this has been a long report, this is an important camera for us astrophotographers.

I wish the news were better, but the 6D Mark II is somewhat of a disappointment for its image quality. It isn’t bad. It’s just that it isn’t any better than than the older 6D, and in some aspects is worse.

Eclipse Rig
The 6D Mark II as part of the rig for shooting the total solar eclipse. The articulated screen will be very nice!
Canon has clearly made certain compromise decisions in their sensor design. Perhaps adding in the Dual-Pixel Autofocus for rapid focusing in Movie Mode has compromised the signal-to-noise ratio. That’s something only Canon can explain.

But the bottom-line recommendations I can offer are:

  • If you are a Canon user looking to upgrade to your first full-frame camera, the 6D Mark II will provide a noticeable and welcome improvement in noise and performance over a cropped-frame model. But an old 6D, bought new while they last in stock, or bought used, will be much cheaper and offer slightly less noise. But the Mark II’s flip-out screen is very nice!

 

  • If you are a current 6D owner, upgrading to a Mark II will not get you better image quality, apart from the slightly better resolution. Noise is actually worse. But it does get you the flip-out screen. I do like that!

 

  • If you are not wedded to Canon, but want a full-frame camera for the benefits of its lower noise, I would recommend the Nikon D750. I have one and love it. I have coupled it with the Sigma Art series lenses. I have not used any of the Sony a7-series Mirrorless cameras, so cannot comment on their performance, but they are popular to be sure.

 

You can find a thorough review of the Mark II’s performance for normal photography at DPReview at https://www.dpreview.com/reviews/canon-eos-6d-mark-ii-review

However, I hope this review aimed specifically at nightscape shooters will be of value. I have yet to test the 6D Mark II for very long-exposure tracked deep-sky images.

— Alan, August 9, 2017 / © 2017 Alan Dyer / AmazingSky.com  

 

Canon vs. Nikon for Astrophotography


Canon and Nikon Cameras

I’ve been an avowed Canon DSLR user for a decade. I may be ready to switch!

This is a decidedly non-pretty-picture blog!

Here, in a technical blog, I present my tests of two leading contenders for the best DSLR camera for nightscape and astronomical photography: the Canon 6D vs. the Nikon D750. Which is better?

To answer, I subjected both to side-by-side outdoor tests, using exposures you’ll actually use in the field for typical nightscapes and for deep-sky images.

Both cameras are stock, off-the-shelf models. They have not had their filters modified for astronomy use. Both are 20- to 24-megapixel, full-frame cameras, roughly competitive in price ($1,900 to $2,300).

For images shot through lenses, I used the Canon L-Series 24mm on the Canon 6D, and the Sigma 24mm Art lens on the Nikon D750.

The bottom line: Both are great cameras, with the Nikon D750 having the edge for nightscape work, and the Canon 6D the edge for deep-sky exposures.

NOTE: Click on the test images for higher-resolution versions for closer inspection. All images and text © 2015 Alan Dyer and may not be reproduced without my permission.


TEST #1 — Noise

The 24.3-megapixel Nikon D750 has 5.9-micron pixels, while the 20.2-megapixel Canon 6D has slightly larger 6.5-micron pixels which, in theory, should lead to lower noise for the Canon. How do they compare in practice?

The scene used to test for noise (here with the Nikon images) showing the development settings applied to both the Nikon and Canon sets. NO noise reduction (colour or lunminance) was applied to any of the images, but Exposure, Shadows, Contrast and Clarity were boosted, and Highlights reduced.
The scene used to test for noise (here with the Nikon images) showing the development settings applied to both the Nikon and Canon sets. NO noise reduction (colour or lunminance) was applied to any of the images, but Exposure, Shadows, Contrast and Clarity were boosted, and Highlights reduced.

I shot a moonlit nightscape scene (above) at five ISO settings, from 800 to 12800, at increasingly shorter exposures to yield identically exposed frames. I processed each frame as shown above, with boosts to shadows, clarity, and contrast typical for nightscapes. However, I applied no noise reduction (either luminance or color) in processing. Nor did I take and apply dark frames.

Noise - Canon

Noise - Nikon

The blowups of a small section of the frame (outlined in the box in the upper right of the Photoshop screen) show very similar levels of luminance noise. The Canon shows slightly more color noise, in particular more magenta pixels in the shadows at high ISOs. Its larger pixels didn’t provide the expected noise benefit.


TEST #2 — Resolution

Much has been written about the merits of Canon vs. Nikon re: the most rigorous of tests, resolving stars down at the pixel level.

I shot the images below of the Andromeda Galaxy the same night through a 92mm aperture apo refractor. They have had minimal but equal levels of processing applied. At this level of inspection the cameras look identical.

M31 (Canon 6D)

M31 (Nikon D750)

But what if we zoom in?

For many years Nikon DSLRs had a reputation for not being a suitable for stellar photography because of a built-in noise smoothing that affected even Raw files, eliminating tiny stars along with noise. Raw files weren’t raw. Owners worked around this by turning on Long Exposure Noise Reduction, then when LENR kicked in after an exposure, they would manually turn off the camera power.

This so-called “Mode 3” operation yielded a raw frame without the noise smoothing applied. Clearly, this clumsy workaround made it impossible to automate the acquisition of raw image sequences with Nikons.

Are Nikons still handicapped? In examining deep-sky images at the pixel-peeping level (below), I saw absolutely no difference in resolution or the ability to record tiny and faint stars. With its 4-megapixel advantage the Nikon should resolve finer details and smaller stars, but in practice I saw little difference.

Closeup of telescope view of Andromeda Galaxy with Canon 6D 4 minute exposure at ISO 800 No noise reduction applied in processing
Closeup of telescope view of Andromeda Galaxy with Canon 6D
4 minute exposure at ISO 800
No noise reduction applied in processing
Closeup of telescope view of Andromeda Galaxy with Nikon D750 4 minute exposure at ISO 800 No noise reduction applied in processing
Closeup of telescope view of Andromeda Galaxy with Nikon D750
4 minute exposure at ISO 800
No noise reduction applied in processing

On the other hand I saw no evidence for Nikon’s “star eater” reputation. I think it is time to lay this bugbear of Nikons to rest. The Nikon D750 proved to be just as sharp as the Canon 6D.

Note that in the closeups above, the red area marks a highlight (the galaxy core) that is overexposed and clipped. Nikon DSLRs also have a reputation for having sensors with a larger dynamic range than Canon, allowing better recording of highlights before clipping sets in.

However, in practice I saw very little difference in dynamic range between the two cameras. Both clipped at the same points and to the same degree.


TEST #3 — Mirror Box Shadowing

An issue little known outside of astrophotography is that a DSLR’s deeply-inset sensor can be shadowed by the upraised mirror and sides of the mirror box. Less light falls on the edges of the sensor.

The vignetting effect is noticeable only when we boost the contrast to the high degree demanded by deep-sky images, and when shooting through fast telescope systems.

Here I show the vignetting of the Canon and Nikon when shooting through my 92mm refractor at f/4.5.

The circular corner vignetting visible in the images below is from the field flattener/reducer I employed on the telescope. It can be compensated for by using Lens Correction in Adobe Camera Raw, or eliminated by taking flat fields.

Demonstrating the level of vignetting and mirror-box shadowing with the Canon 6D on a TMB 92mm apo refractor with a 0,85x field flattener/reducer lens
Demonstrating the level of vignetting and mirror-box shadowing with the Canon 6D on a TMB 92mm apo refractor with a 0.85x field flattener/reducer lens
Demonstrating the level of vignetting and mirror-box shadowing with the Nikon D750 on a TMB 92mm apo refractor with a 0,85x field flattener/reducer lens
Demonstrating the level of vignetting and mirror-box shadowing with the Nikon D750 on a TMB 92mm apo refractor with a 0.85x field flattener/reducer lens

The dark edge at the bottom of the frame is from shadowing by the upraised mirror. It can be eliminated only by taking flat fields, or reduced by using masked brightness adjustments in processing.

Both cameras showed similar levels of vignetting, with the Canon perhaps having the slight edge.


TEST #4 — ISO Invariancy

So far the Nikon D750 and Canon 6D are coming up fairly equal in performance. But not here. This is where the Nikon outperforms the Canon by quite a wide margin.

Sony sensors (used in Sony cameras and also used by Nikon) have a reputation for being “ISO Invariant.”

What does that mean?

A typical Milky Way nightscape with the Nikon D750 and Sigma 24mm Art lens. With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances. Lens correction and basic development setttings applied.
A typical Milky Way nightscape with the Nikon D750 and Sigma 24mm Art lens.
With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances.
Lens correction and basic development setttings applied.
A typical Milky Way nightscape with the Canon 6D and Canon 24mm L lens (original model). With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances. Lens correction and basic development setttings applied.
A typical Milky Way nightscape with the Canon 6D and Canon 24mm L lens (original model).
With no Moon, shot at very high ISO of 6400 and wide aperture of f/1.4 to show image quality under these demanding shooting circumstances.
Lens correction and basic development setttings applied.

In the examples above, the correct exposure for the starlit scene was 15 seconds at f/1.4 at ISO 6400. See how the two cameras rendered the scene? Very similar, albeit with the Canon showing more noise and discoloration in the dark frame corners.

What if we shoot at the same 15 seconds at f/1.4 … but at ISO 3200, 1600, 800, and 400? These are now 1-, 2-, 3-, and 4-stops underexposed, respectively.

Then we boost the Exposure setting of the underexposed Raw files later in processing, by 1, 2, 3 or 4 f-stops. What do we see?

Nikon D750 - Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)
Nikon D750 – Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)

With the Nikon (above) we see images that look nearly identical for noise to what we got with the properly exposed ISO 6400 original. It really didn’t matter what ISO speed the image was shot at – we can turn it into any ISO we want later with little penalty.

Canon 6D - Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)
Canon 6D – Comparing ISO Invariancy from ISO 6400 to 400 (Nightscape)

With the Canon (above) we get images with grossly worse noise in the shadows and with ugly magenta discoloration. Canons cannot be underexposed. You must use as high an ISO as needed for the correct exposure.

This “ISO Invariant” advantage of Nikon over Canon is especially noticeable in nightscapes scenes lit only by starlight, as above. The Canon turns ugly purple at -3EV underexposure, and loses all detail and contrast at -4EV underexposure.

For nightscape imaging this is an important consideration. We are limited in exposure time and aperture, and so are often working at the ragged edge of exposure. Dark areas of a scene are often underexposed and prone to noise. With the Nikon D750 these areas may still look noisy, but not much more so than they would be at that ISO speed.

With the Canon 6D, underexpose the shadows and you pay the price of increased noise and discoloration when you try to recover details in the shadows.

NOTE: In case you think this difference arises only because of the lens, not the camera or sensor, I invite you to check the version of this review at my website page, where there are images taken with each camera shooting through the same optics, the telescope. They show the same difference due to the “ISO invariant” sensor in the Nikon vs. the “ISO variant” sensor in the Canon. 

For more technical information on the topic of ISO invariancy, see DPReview.com and many of their recent reviews of DSLRs, such as this page about the Canon 5Ds/r models. 

Apparently, the difference comes from where the manufacturer places the analog-to-digital circuitry: on the sensor (ISO invariant) or outboard on a separate circuit (ISO variant), and thus where in the signal path the amplification occurs when we boost ISO speed.


TEST #6 — Features

One could go on endlessly about features, but here I compare the two cameras on just a few key operating features very important to astrophotographers.

Nikon Intervalometer Start

Intervalometer:

The Canon 6D has none, though newer Canons do. The Nikon D750, as do many Nikons, has a built-in intervalometer (shown above), even with a deflickering “Exposure Smoothing” option. However, exposure time is limited to the camera’s maximum of 30 seconds. Any longer requires an outboard intervalometer, as with the Canon.

If you use your camera with any motion control time-lapse unit, then it becomes the intervalometer, negating any capability built into the camera. But it’s nice to have.

Small Advantage: Nikon


Interval Length:

When taking time-lapse or star trail images with the Canon I can set an interval as short as 1 second between frames, for a minimum of gaps or jumps in the stars. With the Nikon, depending on whether it is controlled internally or externally, and on the length of exposure, the interval usually has to be no less than 3 to 4 seconds, which can lead to unsightly gaps in star trails.

Small Advantage: Canon


Nikon D750 with Radian

Tiltable LCD Screen:

The Canon 6D has none. The Nikon D750 has a very useful tilt-out screen as shown above. This is hugely convenient for all forms of astrophotography. Only cropped-frame Canons have tilt-out screens. This feature might add weight, but it’s worth it!

Big Advantage: Nikon


Dark Frame Buffer:

The Nikon has none. With Long Exposure Noise Reduction ON, the Canon 6D allows up to four exposures to be shot in quick succession before the dark frame kicks in and locks up the camera. (Put the camera into Raw+JPG.)

This is very useful for deep-sky imaging, for acquiring a set of images for stacking that have each had a dark frame subtracted in-camera, with a minimum of “down-time” at the camera.

Big Advantage: Canon


Live View Screen Brightness:

As pointed out to me by colleague Christoph Malin, with the Nikon you cannot dim the screen when in Live View mode and with Exposure Simulation ON. So it can be too bright at night. With the Canon you can dim the Live View screen — the LCD Brightness control affects the screen both during Live View as well as during playback of images.

Small Advantage: Canon


Canon with GBTimelapse

Software Compatibility:

Canon EOS cameras are well supported by advanced software, such as GBTimelapse (above) that controls only Canons, not Nikons, in complex time-lapse sequences, and Nebulosity, popular among deep-sky imagers for DSLR control.

Small Advantage: Canon


My take-away conclusions: 

• Nikon DSLRs now are just as good for astrophotography as Canons, though that wasn’t always the case – early models did suffer from more noise and image artifacts than their Canon counterparts.

• Canon DSLRs, due to their sensor design, are more prone to exhibiting noise and image artifacts when images are greatly underexposed then boosted later in processing. Just don’t underexpose them – good advice for any camera.


You can read a slightly more complete version of this report at my website at

http://www.amazingsky.com/canon-vs-nikon.html

… where you can also download higher resolution versions of the test images for closer inspection.

My website version contains test images of the ISO Invariance difference on images of the Andromeda Galaxy, as well as comparison images of the Canon 24mm L-series lens vs. the Sigma 24mm Art lens.

All images and text are © 2015 Alan Dyer.

– Alan, August 27, 2015 & Revised August 28, 2015 / © 2015 Alan Dyer / www.amazingsky.com