Just tried my Carl Zeiss 50mm f1.7 on a second C/Y adapter fitted on a EOS 6D body.
After the first exposure, the viewfinder goed dark, so the mirror doesn't flip back.
Only after moving either the lense or the adapter, the mirror slaps back. Does anyone have any pointers on how to proceed?
On a 550D body both adapters work fine.
But I think ive seen this mentioned on the old 5D as well . the mirror of a FF is bigger so I suspect your lens/adapter is protuding a little bit into the mirror box . your 550D is APS-C which is a much smaller mirror . the same proble would exist (only more so) if you mounted an un modded EFs lens and even a modded EFs (like a modded 10-22) will foul the mirror if zoomed all the way to wide .
The 5D Alt crowd were/are into shaving the mirror to stop this
You need to go to the "alternative gear and lenses" forum here on FM for more info. It sounds as if your mirror is hitting the back of the Zeiss lens. This is common to some specific examples of lenses and of 5D, 5DII, etc. If you determine what is hitting the mirror, sometimes you can shave a fin on the back of the lens, or shave the mirror. I may be able to help on that, if that is what is recommend to solve the problem.
svmnb wrote:
Just tried my Carl Zeiss 50mm f1.7 on a second C/Y adapter fitted on a EOS 6D body.
After the first exposure, the viewfinder goed dark, so the mirror doesn't flip back.
Only after moving either the lense or the adapter, the mirror slaps back. Does anyone have any pointers on how to proceed?
On a 550D body both adapters work fine.
As others said it sounds like the mirror is getting caught. NOT a good thing.
The 50/1.7 is known to have mirror complications on a FF Canon - but can be modified to work.
It's probably one of two things - your adapter is too thin - some of the cheap adapters will vary in thickness - if when adjusted to infinity the back of the lens protrudes beyond the adapter - if I remember correctly the C/Y adapter needs to be .150 thick and still reach infinity.
OR - the aperture stem (that thin post) may need to be reduced (shortened). Just use a sharp file and file about .5mm off the length - doesn't need much - mask the lens hole with blue tape first & mark the silvered end cut with a black marker. It can't be higher than the back of the adapter. Shortening the stem may compromise the lens from operating on a Contax camera body.
Many to most C/Y lenses have had their stems modified due to adapter modifications to non-native digital bodies.
Gpop on this forum recommended me a fix that worked well. Put a piece of dental floss between the adapter and the lens. This may provide just the gap necessary to provide clearance. It worked on my 50/1.7 and 5D fairly well.
