Autostack not splitting stacks correctly on sub-second precise timestamps
Hey @Ryan Cush,
I’m not sure but I think there is an issue with the Autostacking, or my interpretation is incorrect.
I have a bracket of 22 images which I have shot at 11 fps. With the default settings, the Autostack feature generates 1 leftovers folder containing the first 3 images of the bracket, and 2 sub-folders. the first, “stack 001”, contains 11 images and “stack 002” the remaining 9.
Based on the setting
this doesn’t seem to be correct, is it?
The other day I returned from a macro walk with 2000 images (which is a shame 🥵) and I fed them into Autostack. There were way too many sub-stacks created.
I recommend to detect brackets maybe based on a fps setting, which could even be derived automatically. For example, 11fps means ~90ms difference between each shot. So, as long as this time difference is constant between two files, the bracket hasn’t completed. If there’s more than that a new bracket begins or it’s a single shot which can be ignored.
I don’t know, would that make any sense?
Cheers,
Klaus
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Comments4
Ryan Cush
Aug 12
@Klaus Cinibulk in the stack you described, is it possible that those frames were longer than ½ second apart, for example due to flash recycle time? I know that happens on my OM-1 in focus bracketing mode, sometimes the flash can’t keep up and it will delay a shot. The math SHOULD be handled correctly, but there is always the chance of a bug. Could you send me some of the source images that are getting incorrectly sorted?
One challenge with using fps is that I don’t think it’s available in the metadata, so the user would have to input it…which I suppose would be fine, as long as your entire session was shot at the same fps. Also, as noted above, if the fps is consistent, which is often the case with focus bracketing, then it would be too “strict” and would create the problem we’re trying to solve, I THINK.
One other thing to try — did you try increasing the spacing to maybe 1 second, or 1.5? Usually my stacks are several seconds (or longer) apart, so there’s probably more wiggle room there.
If there is indeed a code problem here, though, I’d like to get to the bottom of it!
Klaus Cinibulk
Aug 12
The flash cannot delay a shot on my system (A6700 + Godox V1S). The camera keeps the pace, if the flash cannot recycle, you get a black frame. I’m always shooting at the same, highest rate available on my camera.
Here’s the list of files with timestamps from EXIF. It seems to be pretty steady. Are you using the same timestamps?
I’m also attaching the python code the agent created for detecting the brackets.
detect.py
2.1 KB
Ryan Cush
Aug 13
Aha — this was very helpful! Found the problem, and it’s kind of silly. I tested Autostack on RAW files from my OM1, which doesn’t record sub-second precision, so neither does my algorithm (yet the UI lets you pic sub-second values!) Your Sony does record fractions of a second. And the default time-between-shots is 2 seconds, so probably nobody triggered this before. When you set it to 0.5 seconds, it exposed the issue. Should be an easy fix, going to try to get it into tonight’s release. Thanks as always for your help! Give it a test when it lands and make sure it works for you.
In a later release, I’m going make it where you can’t set a gap lower than the precision of the files you’re stacking (today it just warns you on the confirmation screen). And I need to fix the up/down arrows in the Advanced settings, I didn’t realize they were so tiny!
Klaus Cinibulk
Aug 12
BTW: I created a skill in opencode with exactly these instructions, like based on fps, treat stacks with less than N images as single shots. Worked out pretty decent.