Focus stacking workflow

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Dalantech
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Joined: Sun Aug 03, 2008 6:57 am

Focus stacking workflow

Post by Dalantech »

Due to my current techniques opportunities present themselves for me to focus stack, and stacking is something that up until now I haven't done much of. The last time I tried it I converted my RAW files to TIFF and used those for the stack. But I'm wondering about proper work flow.

At what point do you remove dust spots from the frames (do you remove them from individual frames or from the final stacked image)?

Do you convert the RAW files to TIFF, or do you use some other image format? I'm assuming that JPEG is out due to lossy compression (except for the final image).

In my head it makes sense to do the stack first, then do all the post processing on the single frame. But I want to hear from those who have more experience.

rjlittlefield
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Post by rjlittlefield »

The choice of workflow depends on circumstances.

The downside of JPEG is mostly not from compression, but from the fact that sharpening, noise reduction, and color balance are baked into the images and cannot be adjusted much in postprocessing without introducing other problems. The fact that they have 8-bit color also limits flexibility to do curves adjustment in post. These limitations are mostly shared by TIFF images that are shot in camera.

People who do deep studio stacks (hundreds of frames) often do shoot JPEG, but that's after carefully optimizing the lighting and camera settings so they don't have to make adjustments after the shoot.

For shorter stacks, particularly where there's no opportunity to carefully tune the illumination, my standard recommendation is to shoot RAW, convert to 16-bit TIFF using raw conversion settings that are carefully chosen to get the best quality TIFFs, then stack, retouch as needed in the stacking tool, save result as 16-bit TIFF, and do final adjustments and cleanup in Photoshop.

Save the full resolution result from Photoshop as PSD for posterity, before making final images in whatever format and resolution is needed.

If you're using Lightroom, then both Helicon Focus and Zerene Stacker provide plugins that make it simple to export files from Lightroom into the stacking tool, with automatic conversion from RAW to 16-bit TIFF temporary files, using whatever raw conversion settings you have selected with the Lightroom controls.

There's a side issue that might or might not matter to you, but I think I should mention it...

For people who are used to single-shot work with active subjects, making the transition to focus stacking often involves wrestling with how to handle some amount of motion. There's a recent thread at cambridgeincolour.com (HERE) that illustrates the problem. The original poster there also sent email to me, which eventually resulted in my contribution to the discussion there, explaining and comparing how the various methods work. In later email with that photographer, I summarized the issue like this: "My first recommendation is that you reserve stacking for subjects that do NOT move, so that you will not waste time trying to resolve impossible conflicts. However, if you really are committed to stacking subjects that move, then I think the best approach is to learn how to do it manually in Photoshop. Manual positioning and warping will let you do the best alignment of whatever parts you deem most important, and manual masking or cloning will let you do the best job of covering up whatever misalignments remain."

As always, it's a matter of choosing the best tool for the job at hand. The dedicated stacking packages are great for processing well-behaved stacks, but stacks with alignment issues may work better in Photoshop.

--Rik

Dalantech
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Joined: Sun Aug 03, 2008 6:57 am

Post by Dalantech »

Thanks for the detailed reply Rik!

My plan is to learn to take some two to three frame stacks hand held of the subject while it is lethargic -probably no greater than 3x and I plan to shoot at F11, and once I get use to it maybe drop to F8 @ 3x. I'm really looking to get more depth and not necessarily more detail although there should be a slight detail boost at F11 since I'm normally at F14.

No plans to stack anything that might move between frames.

Dalantech
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Joined: Sun Aug 03, 2008 6:57 am

Post by Dalantech »

Just realized that I had to reload my PC a few months ago so I downloaded Zerene Stacker and reinstalled it. I've been a licensed use for quite some time :)

rjlittlefield
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Post by rjlittlefield »

Even so, for 2-3 frame stacks shot handheld, I'm not sure what the best tool will be. In ZS, the PMax method is relentless about preserving detail, which means that the slightest bit of relative movement inside the images will result in streaking or ghosts. That leaves DMap, which might or might not be better than what Photoshop does. I don't know any way to predict, so it's just try it and see.

--Rik

Dalantech
Posts: 694
Joined: Sun Aug 03, 2008 6:57 am

Post by Dalantech »

rjlittlefield wrote:Even so, for 2-3 frame stacks shot handheld, I'm not sure what the best tool will be. In ZS, the PMax method is relentless about preserving detail, which means that the slightest bit of relative movement inside the images will result in streaking or ghosts. That leaves DMap, which might or might not be better than what Photoshop does. I don't know any way to predict, so it's just try it and see.

--Rik
Thanks Rik!

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