It depends on when the crop is being done.iconoclastica wrote: ↑Fri Apr 28, 2023 7:47 amIf I use your formula to calculate the view angle, I find 0.95% either way, inserting average stack depth of 25µm and framewidth = 183.5µm. Should I crop the image before generating the stereo pair, the frame width would become one third of the original and so the view angle about 3%. Experimentally, I found 1% to be optimal, so the original frame width seems the measure to use, or rather, the cropped frame should have used a smaller view angle. How does this angle relate to the frame size?
The key relationship is given at https://zerenesystems.com/cms/stacker/d ... wing_angle :
To be more explicit, the width and depth are as measured at the subject, in the images as they appear while being stacked.subjectStackWidth = frame width at the subject
subjectStackDepth = stack depth at the subject
viewAngle = viewing angle, measured as angular deviation from the usual straight-on view
...
maximumShiftInX = tan(viewAngle) * (subjectStackDepth/subjectStackWidth) * 100%
So, if you stack first and then crop the stacked outputs before making the stereo pair, the shift percentage will not depend on the crop. But if you crop outside Zerene Stacker, or if you use Options > Preferences > Preprocessing > Image Pre-cropping inside Zerene Stacker, then for any fixed angle the shift percentage will depend on the crop because the images being stacked will have a smaller subjectStackWidth but the same subjectStackDepth.
The same issue arises if the images are rotated before stacking, either outside Zerene Stacker or inside via Options > Preferences > Preprocessing > Image Pre-rotation. Any fixed angle requires a larger percent shift in portrait orientation than it does in landscape, because the subjectStackWidth is smaller in portrait.
--Rik
