Focus merge and lens breathing

[lphilpot]

Does Photo's focus merging routine compensate for (and remove) lens breathing? I see nothing in the documentation nor UI specifically about it, but maybe it's just baked in and transparent?

I struggle with focus stacking because my Sigma 17-70 breathes a bit at different focus points. Also where I live we're cursed with trees, grass and other non-stable plant growth. We have no nice stones, nor basically tree-less scenes, so even with apparently no wind there's still a lot of micro-movement in the frames. I'm trying to figure out of the biggest stacking issues are actual movement or breathing.

Thanks.

[NotMyFault]

I made several focus stacks (hundreds) and all were compensating any focus breathing perfectly.

But you need to follow best practices: 

• use best sharpness settings (f/8 or more) and many small steps. 
• Set all to manual and fixed values in camera (iso, aperture, time) and bracket over focus (or motored slide) only

Any movements will kill your focus stack. Focus stacking works only in controlled environments, not in nature with wind.

[lphilpot]

Yep, manual, f/8 to f/11, small steps, all other settings consistent. Maybe my lens (Sigma 17-70) just breathes more...

And I agree about the wind, but I've seen lots of very perfectly stacked nature shots. Nick Page in particular has a killer stacked sunrise image of a highly-foreshortened wheat field in the fore / mid ground with lots of tall wheat, all perfectly sharp front and back. He may have also exposure stacked, I don't recall. I'm about 0.001% as good as Nick but that's how I'll be using it, not for macro.

[lphilpot]

@LeeThorpe, looping you in (if you don't mind) since you discussed breathing to an extent in this thread:

However, it was never explicitly stated whether Photo does or doesn't compensate for it. Can you clarify?

Thanks!

[Old Bruce]

18 hours ago, lphilpot said:

However, it was never explicitly stated whether Photo does or doesn't compensate for it.

I could well be wrong here. I think the way the stacking is done is with the areas of contrast and colours etc within each of the pictures. The areas with high contrast are included and the areas of low contrast are masked out. As opposed to some massive database of lenses and focused distances.

There is a term I recall coming across about lens resolution. The circle of confusion.

Overall I would suggest using a Prime lens, as opposed to a Zoom lens, for this type of work.

[lphilpot]

Well, the reason I ask is that from what I've seen Photoshop does specifically correct for breathing (IIRC in the videos I've watched, although I don't watch too many PS videos). I'm just curious if it's my lens or AP that's at the root of the issues. I did a test months ago using the command line Panotools utilities (enblend, enfuse, etc.) and that came out perfectly sharp, front to back. So far I've not had that happen with AP. But the PT test was contrived -- shooting low across mowed grass and down the street -- vs real world with AP -- landscapes in the wild.

Re: primes vs. zooms, I don't own any primes!  LOL

[Old Bruce]

4 minutes ago, lphilpot said:

But the PT test was contrived -- shooting low across mowed grass and down the street -- vs real world with AP -- landscapes in the wild.

If you still have the original files from the PT test try them with Affinity Photo. Otherwise it is comparing Apples to Fish.