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Author Topic: To focus stack or not to focus stack?  (Read 851 times)

Cyberworld

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To focus stack or not to focus stack?
« on: November 03, 2020, 12:44:03 AM »
I guess the question is rather obvious: I have been taking hundreds of photos of movable complex objects (c.600-1700 photos per object), and due to the requirement for detailed/precise work and the characteristics of the lens used (Sigma 50mm Macro on Canon 5DS R - lens can't focus to infinity) it is necessary on many occasions to take from the same spot multiple photos to have in focus/cover the entire object surface.

Given the situation the question arises: Will it be more or less helpful for Agisoft Metashape to perform focus stacking on the photos? E.g. if I take 4 photos of the same horizontal/vertical angle with different focus points on the object and focus stack them in a photo editor, will this combined focus stacked photo be more helpful for Metashape, or should I keep the original photos? Has anyone experimented with focus stacking in Metashape?

Disclaimer: I've already run the original photos with excellent results (c. 0.5mm error based on targets), but I'm wondering whether focus stacking could have any benefit for the final outcome.
« Last Edit: November 03, 2020, 01:58:23 AM by Cyberworld »

Cyberworld

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Re: To focus stack or not to focus stack?
« Reply #1 on: November 25, 2020, 02:15:14 PM »
Adding on the topic from some tests run:
- Focus stacking does not help Metashape, on the contrary it seems to be throwing it off due to metadata potentially carried by the photo, namely if you forget to tell Photoshop to erase metadata. If a photo says it was captured with certain lens, camera, aperture, shutter, ISO values, but you change the way pixels look due to using focus stacking, the program is thrown off because expectations do not meet reality.
- Also, focus stacking seems to be doing some slight pixel moving at the fringes of the stitched areas, which again is not helpful for Metashape, especially if you run analyses at very high or ultra settings for sparse and dense clouds.

Hope the above help other people with similar questions or thoughts. :)