Why does Live View exposure simulation look too dark at 1:1 with the Canon 100mm f/2.8L Macro?
Asked 9/3/2016
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On a Canon EOS 600D/T3i with the EF 100mm f/2.8L Macro IS USM, Live View exposure simulation appears to darken significantly as focus is moved toward 1:1 magnification. This seems related to the lens’s effective aperture becoming smaller at close focus, but the preview and histogram look at least about a stop darker than the actual captured image. The issue is most noticeable at wider apertures such as f/2.8 to f/5.6. Is this expected behavior, or a Live View/exposure simulation bug?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
9y ago
2 Answers
3
I'm risking answering this, so go light. I have a WORKAROUND, and a manufacturer solution, but the solution can only come from canon or hacking your firmware
This is an interesting question, THANK YOU!
I just tested the Canon 5D SR firmware 1.0.1 R and saw no issues! However, I tested previously the 5D III firmware v1.3.3 and I saw the exact same results as you did! I started to type a comment to your post, but testing lead me to the following:
5D III
I expected perfect results, but after making test photos I did remember the issues you mentioned on a previous photo shoot I did with an older firmware. That is why i quit using the lens. After testing and reading your excellent question, a perfect solution would most likely need to be from Canon as some sort of firmware or software update, but fear not. The testing led me to a great workaround that is OKAY. I noticed that the compensation meter exposes properly both in live view and in the actual photo. Although you will not get an accurate representation of the image or histagram before firing you can rely on the exposure compensation meter to give accurate feedback of the overall, spot or evaluative metering modes for the final image capture based on your settings.
The exposure compensation meter is accurate in both the photo and live mode:
What i did with the 5D III (WORKAROUND):
- turn on live view display
- set your shutter or aperture to the level that matches a good evaluation on the exposure compensation meter.
- Increase the ISO by doubling twice, so 400 becomes 1600, etc. (This is adding 2 stops of exposure through ISO.)
- focus
- turn back the ISO by doubling down! (had to say that)
- then fire
- your exposure should be very similar to the live view display when quadrupling ISO.
Alternatively for the 5D III (untested),
- install magic lantern
- hack live view refresh rate?
- might work?
Canon 5D SR (Just Shoot, Normally)
- Attach lens, shoot in live view.
- everything works.
Here are representations of the OP look of the images:
Live view:
NOTE: The histagram reflects the image look in live view, but the exposure compensation meter stays the same as the actual photo that will be exposed.
Actual Photo:
Hope this helps someone.
Originally by user41105. Source · Licensed CC BY-SA 4.0
user41105
9y ago
0
Generated from our catalog & community — verify before relying on it.
Based on the reported behavior, this appears to be a Canon Live View/exposure simulation issue rather than normal exposure behavior. Macro lenses do lose effective aperture at close focus, so some darkening in preview is expected, but users reported that certain Canon bodies over-darken the Live View image and histogram at 1:1 with the 100mm macro.
From the answers, the mismatch was seen on bodies like the 6D and 5D III, especially in Manual mode with a fixed ISO and apertures between f/2.8 and f/5.6. In Av, Tv, and P modes, or when Auto ISO was enabled, the discrepancy was not observed.
So the practical conclusion is:
- some darkening from effective aperture is normal;
- if Live View is much darker than the final photo, that is likely a firmware/software quirk;
- a true fix would have to come from Canon firmware.
Workarounds: use Auto ISO, switch to Av/Tv/P for composing/exposure preview, or trust the actual meter/test shots rather than the Live View histogram at high magnification in Manual mode.
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UniqueBot
AI9y ago
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