Canon 5D III and micro focus adjust

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Canon 5D III and micro focus adjust

dgdg
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p.1 #1 · Canon 5D III and micro focus adjust

Trying to mfa my 5DIII and 400 mm do with FoCal. Photos at 50x focal length with large test target appear to be in focus to the naked eye with zero mfa. However, I had to mfa the 400mm lens on my 5D II with Focal and it did help at +6. I am trying to see what mfa, if any, it needs on the 5D III.

I am using FoCal plus and despite several scenarios outside in decent light, Focal cannot complete. I am using a tripod, geared ball head, and target is attached to a wall. FoCal notes inconsistencies with lens/camera and cannot nail a recommended mfa after 50 shots. I did some manual shots with a cable release. I can see at -10 and +10 performance is worse than 0 mfa. In between this, results are hard to parse.

I recall mfa changes to be more dramatic when using the 5D II and the 400mm do.
Any suggestions on how to confirm my mfa setting?

Nov 12, 2012 at 03:21 PM

Dave Jr
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p.1 #2 · Canon 5D III and micro focus adjust

So you're at roughly 65 feet? I would try reducing the distance until I could get a completed result, then try shooting distant objects with the given adjustment and see if you are happy with the results.

Nov 12, 2012 at 03:32 PM

dgdg
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p.1 #3 · Canon 5D III and micro focus adjust

I'll try smaller distance, referring to FoCals docs, looks like 40ft would be ok.

I'm getting shutter speeds of 1/2 sec to 1/50. This may be the issue with a 400mm lens. Anyone note poor performance in lower light?

Nov 12, 2012 at 06:40 PM

mco_970
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p.1 #4 · Canon 5D III and micro focus adjust

Yeah. You need optimal lighting - 13-14 EV's is great. And for long teles I bump up the ISO to 320 for the tests (this is a feature in the pro version) so that shutter speeds are high.

Nov 12, 2012 at 06:43 PM

dgdg
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p.1 #5 · Canon 5D III and micro focus adjust

thank you both.
I put a spot lamp on the paper target and increased the iso to 320. Shutter speed went to 1/400. Calibration went through quickly. Even had time to do my 50mm. I did run that one three times as the second attempt failed. The first and last test gave very similar results. If it stops raining I can put the extender on my 400 mm and go outside with my light.

Nov 13, 2012 at 01:38 PM

Fr3lncr
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p.1 #6 · Canon 5D III and micro focus adjust

While I really like FoCal, it isn't perfect as it either crashes on me or fails to achieve a good enough result about 20-30% of the time.

What I find helps is with zoom lens to choose a focus method that causes the lens to move the most. So with my 70-300 L, on the 300mm side, I'll choose 'Defocus near' rather than 'Defocus far'. This gives more consistent ratings resulting in a higher result confidence.

Essentially, play around with the settings. I do the AFMA test three times for each setting as I want at least two results the same before choosing that setting. Doing 5-6 lenses takes me a long while to finish everything.

And if I get any sort of error, I'll exist the program and turn off the camera and start again rather than trying to keep going since the software just doesn't seem to recover from issues at all.

I still like it though. Just not perfect.

Nov 16, 2012 at 08:27 PM

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