Why are my StackShot macro images darker than the EOS Utility test shot?
Asked 3/2/2018
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2 answers
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I’m photographing small insect specimens with a Canon EOS 6D on a StackShot macro rail. A single test shot taken through Canon EOS Utility looks much brighter, while the images captured during a StackShot sequence are much darker, even though the flash appears to be firing.
I’m trying to figure out whether this is a timing/sync issue between the flash and shutter in StackShot, or an exposure/lighting problem. I’ve already replaced the camera and flash batteries and restarted everything.
What should I check when a stacked macro setup produces darker frames than a single test shot?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
1
Not an answer but a few things to check:
Are you moving toward or away? If the flash is being set at the same level, then as you move toward, you get more light reflected. If moving away, less light. It doesn't take a lot of move to make a significant difference.
You can check this as a cause by mounting the flash off camera.
Are you using automatic exposure/automatic flash? Find the right flash level manually, and use that.
The white background may be fooling the light meter. I generally find that viewing macro level objects on white on screen has a lot of glare. Consider using a neutral grey or a black background. (Art stores have an amazing variety of coloured cardboard.
If this is the case, you may have the opposite problem on a dark background: The stacked image is overexposed.
Have you inquired with the makers of the software?
Originally by user17873. Source · Licensed CC BY-SA 4.0
user17873
8y ago
0
Generated from our catalog & community — verify before relying on it.
It may not be a sync failure if the flash is firing; exposure can change during the stack.
Things to check:
- Direction of travel: If the rail moves the camera/specimen farther from the flash, each frame can get darker very quickly at macro distances. Moving closer does the opposite.
- Flash placement: If possible, mount the flash off-camera so the distance/angle to the subject stays more consistent during the stack.
- Manual exposure/flash: Avoid automatic exposure or TTL flash for stacking. Set the camera and flash manually once you find the correct exposure.
- Background influence: A bright white background can fool metering and create glare. Try a neutral gray or black background instead.
So the first troubleshooting steps are to confirm whether the stack changes subject-to-flash distance, switch to fully manual exposure/flash if you haven’t already, and test with a less reflective background. If those changes make the stacked frames consistent, the issue is likely exposure variation rather than shutter/flash timing.
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