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Message |
    
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 98
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 16, 2012 - 07:51 am: | 
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Hello,
I just developed the first test roll from the Canon New F1 I got a while ago. I noticed a slight back focus issue. Since most pics were taken with a 28mm wide angle lens and rather small apertures, it is not really noticeable, until I switched to a 50mm lens for closer pics and wide apertures.
Here is a sample:
http://images46.fotki.com/v297/photos/4/1233394/9837650/Scan1212150008-vi.jpg
I carefully focused on my son (center of pic) and even asked him to "hold still while I focus manually". But you can see Jerry in the back clearly in focus.
I took a careful look at the camera and the mirror seems to be fine and seating properly.
I carefully removed the focusing screen and it seems I'm the first to ever do so. No marks of ever been molested whatsoever.
I tested the same lenses in a AE-1 and they are working properly.
At about 8 feet away, the AE-1 focuses at the 7ft mark but the F1 indicates 10 ft. Definitely the issue is in the F1.
Is this a known issue? I'm thinking maybe shims to lift the focusing screen may help.
Any comments on this?
Thanks,
Ismael |
Zombicams
Tinkerer
Username: Zombicams
Post Number: 4
Registered: 12-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 16, 2012 - 10:58 am: |
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Take off the lens and check the mount on the camera. Try moving it in all directions. I had an AV-1 once and the mount was loose so it caused a problem. When the lens was put on it, the lens would be on tight and solid but still be moving around because the mount on the camera was loose. I solved the problem temporarily by oozing glue down past the mount but I don't suggest it as a repair solution. |
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 99
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 17, 2012 - 05:05 am: |
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Thanks for the suggestion. I checked the mount and it is rock solid.
I think I have isolated the problem to the mirror/focusing screen. I did some more testing with the lens scales and the AE-1 body and I think the film plane is getting the correct focus.
Thanks,
Ismael |
