Last week, I went out to photograph the comet NEOWISE before it disappeared. I had never seen or photographed a comet before, and it far exceeded my expectations! I filmed my process along the way, including several tips for star photography (and of course comet photography too).
Here’s the video, which we just published on YouTube:
I’ve gotten questions about how much image quality improvement this stacking technique can produce. Technically there’s no upper limit, but the idea is that each time you double the number of photos that you stack (i.e., 2, 4, 8, 16, 32, 64, and so on), you’re going to improve your image quality by about one stop. Because I stacked 53 images in this case, it’s about 5.7 stops of image quality improvement over a single photo. Because my single photos are at the high ISO of 16,000, the final image works out to be roughly equivalent to ISO 320 in image quality.
If you prefer the visual explanation – who wouldn’t!? – here’s a comparison between a single image and the final stack (with heavy noise reduction applied to the single image):
It’s a massive difference, and these aren’t even 100% crops. Image stacking (or a star tracker) is the way to go when you need to shoot any deep-sky astrophotography subjects.
One thing I mentioned in the video but also want to point out here is that the bluish-green bit at the bottom of the comet is called the “coma” (not to be confused with the lens aberration coma in photography), and it’s actually the comet’s atmosphere! One of my main goals was to capture that in a photo, and I almost jumped for joy when the final image stack showed it so clearly.
If you want to photograph NEOWISE too, you’re definitely running out of time, although it should still be visible about 1.5-2 hours after sunset if you can find an area without too much light pollution (and you live in the Northern Hemisphere). Bring binoculars! Finding NEOWISE should still be pretty easy; it’s a bit below and to the left of the Big Dipper. But it’s getting dimmer each day now, and before long you’ll only be able to see it with your camera or binoculars, and not the naked eye.
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Great pictures and explanation! Also nice to read some of the constructive discussion below.
My personal attempt wasn’t as good as I had hoped, but I wasn’t in a photogenic location and I was getting eaten alive by mosquitoes. I was also taking ~15s exposures @F1.8 ISO400 since I didn’t know about image stacking and was trying to minimize noise. Wish I had known, I surely would have gotten a much better result! I always thought a tracking mount was required if you wanted to get rid of star lines. Going to have to do a lot more reading into image stacking before attempting this kind of thing again… in 6000 years or whatever it was lol
Great video! The video and the comments are very helpful. I’ve been out once to photograph Neowise, and I hope to get out again at least once. Thank you.
Good job, Spencer! The first comet tail is a dust tail, and the second one is an ion tail. That is definitely airglow you captured. I’ve been wondering if the 20mm f/1.8 S would be a great astro lens for the Z series. Looking forward to your review.
Regarding Lightroom and stacking, how are you handling lens distortion? Typically it gives a terrible moire effect and you don’t enable lens profile corrections until after stacking with ACR / Lightroom, but Adobe has baked it in with the Z cameras where you can’t disable it. Many Nikon photographers are moving on to Capture One or other raw converters as a result for night photography with the Z models. I understand there is a beta of Starry Landscape Stacker that supports raw files to get around that silly “feature”, but I wonder if the lens profile data could be stripped in the EXIF data before importing in Lightroom to get around it for apps like LRTimelapse? I’m still happy with my D850 and haven’t experimented with that idea yet…
Thank you, Aaron! Good to hear from you, I feel like it’s been a while.
Even though I showed Lightroom at the end of the video, I actually am exporting from Capture One (and doing preliminary contrast reduction/brightening there) into Starry Landscape Stacker. The patterned noise problem is ridiculous in Lightroom, and I don’t think there’s a way around it. I have no idea why Adobe doesn’t allow us the option of reverting to the uncorrected shot.
I hadn’t heard about the beta Starry Landscape Stacker that accepts raws! If it works well, that would be a nice time-saver (and space-saver given how quickly 50+ TIFFs can get out of hand).
The 20mm review is actually the next video I’m planning, and we’ll put out the article at a similar time.
I think it’s still a private beta at the moment. I have no idea how good the raw converter is. It doesn’t output a raw file because it isn’t using Adobe DNG Converter, so it avoids the moire with Z cameras, but doesn’t give you a chance to adjust white balance, sharpening, etc. on raw data either.
Focus stacking with Helicon Focus is another problem for Z cameras because their RAW-to-DNG workflow uses Adobe DNG Converter and has the same moire issues with embedded lens profiles that can’t be disabled. It’s ridiculous.
I’m wondering what lenses you use, Aaron. The lens profiles for the Z lenses come from Nikon. Nikon has a macro far away in the funny regions of their “roadmap”, and for other macros they don’t provide inbuilt lens profiles. Oops, just learnt a new thing: Nikon lenses in general (also the ones adapter on FTZ) show the “manufacturer lens profile” in C1, and deactivating it does alter the picture. Didn’t know that.
The question is, who is to blame? Nikon, because some of their lenses would look rather bad distorters without the help of a software profile? The apps you mentioned because they can’t switch off that function?
My version of Helicon Focus is old and since I don’t want to choose between an expensive “life long” or “annually” version I will not update it. So I can’t say anything about it’s current qualities. A friend of mine tried various stacker apps and ended up with “Zerene” and “Focus Stacker” by Olga Kacher. He found both of them superior to Helicon. I use Affinity Photo and JPGs out of Camera, as I can control the studio scene and repeat it, if necessary.
I shoot a lot of focus stacked gigapans with a 70-200mm f/2.8 or longer, not just macro lenses. Helicon Focus has a good batch mode and raw-to-dng workflow for this. I haven’t used Capture One very much, other than an old demo, so I’m not sure how lens profiles are handled in it, but Adobe really bugs me with not being able to disable lens profile corrections for advanced panoramas and stacking. Adobe does the same to my DJI drone and I’d rather let PTGui Pro handle lens corrections as it does a far superior job when it comes to 360 panos. I think I’ll play around with exiftool and see what I can strip for lens information to fool Adobe with these cameras… ;-)
Hi, Aaron and Spencer…
The next versions of Starry Landscape Stacker and Starry Sky Stacker will support raw. This is mentioned in the documentation on the web site. I’m currently beta testing SSS. I’ve reported some minor issues — but otherwise think this will be a welcome addition to the software.
I also use Deep Sky Stacker (running in a VM) with exported TIFFs even though it supports raw. The output result has white balance controls.
For both DSS and SSS/SLS I prefer to use exported TIFF because I can control lens distortion, vignetting, white balance, etc., before stacking.
Yeah, I was thinking the same would happen with SLS and raw files… unless it outputs a DNG or similar raw file where you can control all these things after stacking. Otherwise, I prefer TIFF as well.
Outstanding composition, Spencer – no, compositions!
And during this long night always getting the video right – at first I thought you stood the whole time next to the camera but you must have changed places. Really cool, thanks for sharing!
Much appreciated! I ended up changing places a few times, especially for the lake reflection shot at the end.
Outstanding photos Spencer! I love the lake reflection!
I too was trying my best to capture the coma although I was not able to capture the blue tail. I was using my 200-500 zoom on a D500. The linked picture is a stack of only 15 but I’m pretty happy with it (except for that blue tail). I may try a different lens if I’m able to get out again.
This site is a great deal of help.
Keep up the good work and thanks!
That’s awesome! The coma looks great in your shot. I’ve heard that Neowise’s tails are changing somewhat in appearance, which may have contributed toward the less visible blue band in your image.
Either way, glad you were able to get out and photograph it! Good to see that it was still so visible on July 24.
Where did you shoot the images? Are the green “clouds” on the last image northern lights?
Colorado, pretty sure it’s not the Northern Lights, but rather airglow instead: en.m.wikipedia.org/wiki/Airglow
I’ve never captured it quite this strongly and was very excited to see it here! It’s in both the lake reflection shot as well as the vertical telephoto shot (though the yellower tint near the horizon in both cases is likely just light pollution).
Hi Spencer, nice images, but shooting at ISO16000 was a mistake – you lost a lot of dynamic range because of that, and as a result your stars are blown out. If you had shot the sequence at ISO 800 – 1600 you would have captured just as much detail in the dark parts (recoverable through curves adjustments after stacking) while maintaining colours in the stars.
That’s probably true, although I do want to be wary of too low an ISO because Lightroom and other software have issues recovering beyond 3-4 stops of exposure (even when the detail *is* there in the RAW file; the software’s algorithm is at fault).
In hindsight, I’d probably have chosen ISO 6400. ISO 800 at 3 seconds is equivalent in brightness to ISO 100 and 25 seconds for Milky Way photography, which I don’t trust any software to recover even with a fully ISO invariant sensor.
Spencer, that might be true for unstacked photo’s, but the whole idea of stacking is to reduce the noise floor by so much that pushing the exposure in post is no longer an issue. (up to a point, of course) Believe me, a 3-4 stop push of a stack is considered a *very* conservative amount in astrophotography ;-)
I’m sure you are familiar with the following website, but for those reading along, this graph illustrated the DR penalty paid by shooting at very high ISO:
No disagreements really, I should have used a lower ISO there.
That said, most of the exposure pushing I do is prior to the stacking, where I naturally get color shift issues when boosting lower ISOs. Do you tend to increase brightness after stacking instead, or is it that the color shift issues average out in the same way as noise when stacked?
I’m still trying to figure out the best practices here, and played it too “safe” (in the sense that I knew I’d get a result that looked good, though not optimal dynamic range) by using the higher ISO. But I’m all about optimizing things like this and want to do it with maximum image quality in the future.
One thing I meant to add as well, is that the decrease in dynamic range at higher ISOs certainly exists, but not necessarily in the way that people think. If a photo at ISO 6400 doesn’t blow out any highlights, a photo taken at ISO 3200 and boosted in post by one stop (all other settings equal) won’t have any more dynamic range. At best, if ISO is invariant on that camera between those two ISOs, the results will be equivalent. In practice, there’s probably a slight *benefit* to dynamic range at the higher ISO in such a case.
I know you know this because you’re referring to blowing out the stars’ highlights at my ISO, but I wanted to add it for those who didn’t know.
I was lucky the first week being able to capture it with clear skies. After that it has been nothing but clouds! I even traveled two hours away to frame it with a famous geological feature but the clouds never let up. I have since given up. Nice photo!
Glad that you got to see it! I’d been wanting to make this video since the comet first became visible, but afternoon thunderstorms are apparently a requirement in Colorado in the summer. I was really lucky to have this clear night!
Good job Spencer! I am glad the pictures turned out okay.
Thank you, Zigman! I was really glad they did as well.
Outstanding photographs Spencer!! Wish I could have been back in Santa Fe last week to photograph this comet but Durham’s terrain, light and humidity would not allow.
Thank you! Yeah, unfortunately light pollution makes this pretty much impossible. I moved out to Colorado last year and have been amazed how much clearer the skies are here (previously lived in Nashville and Chicago).