I test nine programs for processing raw files for the demands of nightscape astrophotography.
When using DSLR or mirrorless cameras for astrophotography, the best practice is to shoot raw files, not JPGs, for the finest image quality. But akin to film, we say that raw files need “developing” in order to turn their flat-looking images into a “wow” photograph.
What raw developer software is best? To find out, I compared eight programs, pitting them against what I and many photographers consider to be the standard, Adobe Camera Raw (the Develop module in Adobe Lightroom is essentially identical), testing them on a challenging nightscape scene.
In addition to Adobe Camera Raw, I tested (in alphabetical order):
- ACDSee Photo Studio
- Affinity Photo 2 (from Serif)
- Capture One 23
- Darktable 4
- DxO PhotoLab 6
- Exposure X7
- Luminar Neo (from SkyLum)
- ON1 Photo RAW 2023
The eight contenders can all be purchased as perpetual license software. However, as listed below, some also offer the option of subscribing for additional perks and cost savings.
I tested only programs that are offered for both MacOS and Windows. I tested the MacOS versions. I did not include:
- RawTherapee — As of early 2023, its MacOS version 5.8, last updated in early 2020, would not open the Canon CR3 raw files I used in the test. To try it for yourself, download the program here. It’s free!
- PixInsight — This specialized program is for calibrating and processing deep-sky images. My test was on nightscapes, which “PI” is not designed for.
I tested all nine programs on a sample nightscape image, shown below, using each program’s many adjustments as best I could to match the results from Camera Raw. I did not test them on deep-sky images, as the orthodox workflow is to use specialized software such as PixInsight to calibrate and stack the raw images, then export 16-bit TIFFs for further editing, bypassing any raw developer.
Only two of the programs, Affinity Photo and ON1 Photo RAW, can also layer images for composites and stacks, just like Adobe Photoshop. I did not compare those capabilities.
NOTE: This is an abridged version of an even more extensive review I published at my AmazingSky blog, which can be found here. The full-length test presents more details about shadow recovery, local masking, and noise reduction, as well as suitability of the programs for processing panoramas and time-lapse sequences.
THE TEST RESULTS
Adobe Camera Raw (included with Photoshop, Adobe Bridge and Lightroom)
Cost: $10 a month, or $120 a year by subscription for 20 Gb of cloud storage (all prices are U.S. $)
Website: https://www.adobe.com
Version tested: 15.1
Adobe Camera Raw (ACR) is the raw development utility that comes with Photoshop and Adobe Bridge, Adobe’s image browsing application. ACR is equivalent to the Develop module in Lightroom, Adobe’s cataloging and asset management software. All programs are included in an Adobe Creative Cloud Photo subscription (at the cost listed above).
IMAGE QUALITY: Excellent
PROS: While lacking advanced “AI,” Camera Raw’s classic noise reduction did smooth noise acceptably, while retaining star colors and Milky Way structures, without introducing AI artifacts. Its Shadows slider affects just the dark tonal areas for excellent recovery of details in landscapes lit only by starlight. ACR does use AI machine learning to create masks in one-click, to aid applying separate adjustments to the sky and ground. I found the masks were quite accurate.
CONS: ACR is available only by monthly or annual subscription with the other Adobe programs in the suite. ACR (and Lightroom) lacks the more advanced AI noise reduction, sharpening, and one-click special effects of some competitors. Adobe Bridge, a key part of the suite, tends to be neglected by Adobe, and suffers from bugs and deficiencies that go uncorrected.
ACDSee Photo Studio
Cost: $100 to $150, depending on version. $50 on up for annual major upgrades. Or by subscription from $70 a year.
Website: http://www.acdsystems.com
Version tested: 9.1
I tested Photo Studio for Mac v9. Windows users have a choice of Photo Studio Professional or Photo Studio Ultimate, with Ultimate also offering layer-based editing, making it similar to Adobe Photoshop. Photo Studio Professional is similar to the Mac version I tested, but with the addition of panorama and HDR functions missing in Photo Studio for Mac.
IMAGE QUALITY: Fair
PROS: ACDSee offers good image management functions, making it suitable as a non-subscription Lightroom alternative. Its unique Light EQ panel provides an equalizer interface for making very selective tonal adjustments. While it worked well, the results tended to look too harsh and contrasty.
CONS: Lacks any Auto Lens Corrections — distortion and vignetting corrections have to be dialed in by eye. It added unacceptable halos around stars. When brushing on local adjustments, there is no edge detection to easily mask ground and sky. Local adjustments are limited to only Exposure, Saturation, Fill Light, Contrast, and Clarity.
Affinity Photo 2
Cost: $70. Upgrades are free except for rare whole-number updates (in seven years there’s been only one of those!). No subscription plan is offered.
Website: https://affinity.serif.com
Version tested: 2.0.3
For astrophotographers, Serif’s Affinity Photo has some impressive features, such as the ability to calibrate and align deep-sky images, and to stack images for noise reduction. The program’s strength is as a low-cost, layer-based editor using features offered in its Photo Persona. However, I tested the raw editing adjustments of its Develop Persona.
IMAGE QUALITY: Fair (for its Develop Persona) / Good to Excellent (for its Photo Persona)
PROS: Affinity can serve as an excellent non-subscription, layer-based editor in place of Adobe Photoshop, and with more advanced features than the other popular choice, the free program GIMP.
CONS: Affinity’s Develop Persona for raw files is very basic. While it nicely smoothed noise, it also removed star colors. Affinity’s Shadows slider produced flat results. Unlike all the other programs tested, Affinity Photo lacks any form of image browsing, cataloging or asset management, making it very difficult to identically process a set of images, a common need for all astrophotography. It lacks any AI auto-masking in any of its Personas.
Capture One 23 Pro
Cost: $299. 33% off (about $200) for annual major upgrades. By subscription for $180 a year.
Website: https://www.captureone.com/en
Version tested: 16.0.1.17
Capture One is a powerful raw developer, plus image management and cataloging program. It is the most costly to buy, upgrade each year, or subscribe to. It cannot replace Photoshop, only Lightroom.
IMAGE QUALITY: Excellent
PROS: Capture One has excellent Shadow recovery. The dark landscape brightened without becoming flat or grey. It offers local adjustment layers, though lacking any edge-aware option. It has a very good panorama stitching function.
CONS: While it smoothed noise very well, Capture One tended to bloat stars and soften fine detail with its Single Pixel control turned up even to one pixel. Local adjustments require more manual work than programs equipped with AI-driven selection tools such as ACR and Luminar.
Darktable
Cost: Free.
Website: https://www.darktable.org
Version tested: 4.2.0
Darktable is a free, open-source raw editor intended to compete with Lightroom but with a much more complex user interface that can be a challenge to navigate.
IMAGE QUALITY: Poor
PROS: It’s free! And it offers many adjustments not found elsewhere, such as a unique Astrophoto Denoise panel. The technically minded will enjoy experimenting with all the options.
CONS: Darktable’s noise reduction routines seemed to wipe out star colors and fine structures in the Milky Way. Its Shadows slider produced a flat result. The program lacks any local adjustments. I struggled with Darktable’s complex panels, all for poor results. It frequently crashed during my testing.
DxO PhotoLab 6 ELITE
Cost: $219. $99 for annual major upgrades. No subscription plan is offered.
Website: https://www.dxo.com
Version tested: 6.1.1
DxO PhotoLab is a very complete raw developer with good image management and a well-designed interface. PhotoLab is also available in a $140 ESSENTIAL edition but without the DeepPrime noise reduction and ClearView Plus haze reduction of the ELITE edition, both useful features for astrophotos.
IMAGE QUALITY: Excellent
PROS: Its DeepPrime AI noise reduction is excellent, but if applied too strongly it can add artifacts to the image. While its Shadow recovery is good, DxO’s best feature is “Smart Lighting,” which can work wonders on a nightscape with one click. DxO offers excellent automatic lens corrections.
CONS: Local adjustments are added with brushes through its unique Control Point interface with equalizer-like mini-controls, which is quirky but can work well once you get used to it. DxO lacks any panorama stitching as found in Adobe Camera Raw, Affinity Photo, Capture One, or ON1 Photo RAW.
Exposure X7
Cost: $129. $89 for annual major upgrades. No subscription plan is offered.
Website: https://exposure.software/
Version tested: 7.1.5
Formerly known as Alien Skin Exposure, Exposure X7 is a surprisingly powerful raw editor, with all the expected adjustment options. It enjoys major annual updates, so is kept up to date, though it lacks any AI functions that are now popular in software.
IMAGE QUALITY: Fair
PROS: Exposure offers a full set of tone and color adjustments, and essential image management functions. It has good local adjustment layers though with no AI or smart brushes to automatically detect edges.
CONS: Its Shadows slider lowers overall contrast, requiring boosting Contrast and Blacks to return the image to a pleasing tonal balance. Its noise reduction smooths noise well but also wipes out details and structures, and its sharpening adds dark halos to stars. There is no panorama function. It, too, frequently crashed during my testing.
Luminar Neo
Cost: $149. $39 to $59 each for individual Extensions. $179 for Extensions pack. By subscription for $149 a year including Neo and all Extensions.
Website: https://skylum.com/luminar
Version tested: 1.6.2
Luminar Neo from Skylum offers the expected raw editing adjustments along with many powerful one-click AI effects and tools, some offered as extra-cost extensions in a controversial à la carte sales philosophy. Neo works well as a plug-in for Photoshop or Lightroom.
IMAGE QUALITY: Good to Excellent
PROS: While its Shadows slider under its DevelopRAW panel was too broad, a liberal application of its SuperContrast slider returned the image to a better appearance. Its AI masks can automatically select the sky and landscape elements for easy local adjustments. The final results can look quite good.
CONS: Luminar Neo’s catalog function is very basic. The program lacks any Auto Lens Corrections and brushing on local adjustments manually is crude. Its Noiseless AI extension did a poor job on stars. Neo was impossibly slow when copying and pasting settings from an image to a large set and then exporting the developed frames, which is necessary for preparing time-lapse sequences. Its function for layering and stacking images was buggy and unusable.
ON1 Photo RAW 2023
Cost: $99. $60 for annual major upgrades. $70 for individual plug-ins, each with paid annual updates. By subscription for $90 a year including all plug-ins and updates.
Website: https://www.on1.com
Version tested: 17.0.2
Of all the programs tested, this is the only one that can truly replace both Lightroom and Photoshop, in that ON1 Photo RAW has cataloging and raw developing (like Lightroom) in addition to image layering and masking (like Photoshop). While the main program and ON1’s optional plug-ins can all be purchased as perpetual licenses, the total cost makes an annual subscription the cheapest way to get – and maintain – the full ON1 suite.
IMAGE QUALITY: Good
PROS: ON1 has very good NoNoise AI noise reduction but it has to be lowered in intensity from the defaults to avoid artifacts. ON1 has good local adjustment layers though its new AI Super Select function is flawed in its accuracy (Select Sky misses most stars). ON1 has excellent finishing-touch Effects, also available as a separate plug-in for Lightroom and Photoshop.
CONS: As a single “do-all” program, I’d recommend ON1 more highly, but … It leaves dark halos around bright stars from over-sharpening that cannot be turned off. Its Shadows slider affected too wide a range of tonal values, making the scene look flat, though this can be mostly overcome with the Contrast, Blacks and Midtones sliders. While it can layer images, it has no Stack Modes (found in Photoshop and Affinity Photo) for noise smoothing.
SUMMARY COMPARISON TABLE
In this table I rate the programs by key factors I deem critical to good nightscapes such as: lens corrections, noise reduction, shadow recovery, local adjustments, plus overall image quality and the inclusion of advanced features such as Panorama and HDR Merge. Copy-and-paste settings and batch export functions are critical for processing sets of time-lapse images.
- = Feature is present; ticks the boxes!
— = Feature is missing
Partial = Feature only partially implemented (e.g., has distortion correction but not vignetting correction or has limited cataloging functions)
I judged other features on an admittedly subjective scale of Poor, Fair, Good, or Excellent, based on my overall impressions of the reliability, options offered, quality, and/or speed of operation.
TEST FOR YOURSELF!
With the exception of Luminar Neo, all the programs I tested are available as free trial copies. Do try them out on your images and workflow. Your mileage may vary from mine, and you might find you prefer a program that was not one of my top picks.
My conclusions? Adobe software still provides first class results, and it’s my first choice. But if it’s a good raw developer you are after for astronomy work without paying for a subscription, try Capture One 2023 or DxO PhotoLab 6. Try Affinity Photo if you want a good non-subscription Photoshop alternative for stacking and layering developed raw files exported out of Capture One or DxO PhotoLab, as Affinity’s own Develop Persona module is poor and lacks image management.
NOTE: For a comparison of programs made specifically for noise reduction, see my test of seven programs here at AstroGearToday.
