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  1. #1

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    My Mamiya Won't Focus to Inifinity!

    I was thinking it might have something to do with the lens but I still have no idea since it is a Mamiya lens and I got it as a bundle from KEH.com.

    The camera is a Mamiya 645E and the lens is a Mamiya-Sekor 80mm f/2.8 N. Is there anything about this lens/camera combo that causes it to not focus to infinity? I don't think it's even infinity unless infinity is actually pretty close. I live in an apartment building that used to have a fraternity house inbetween the other matching apartment building and I can't focus on things that are past the frat house, like trees. They look decently close with the split prism or even in focus but when I actually look at the sharpness of trees and anything else, nothing really LOOKS in focus. I have the diopter set to -1 though, could this have anything to do with it? I know that when you have lens adapters it can offset infinity focus or certain macro attachments but the diopter is the only thing I can think of. I haven't had a chance to really check out the negatives to see if I'm just hallucinating (I doubt it) but I have also managed to do what I could to get the infinity stuff in focus by stopping down to say f11 and by using the depth of field preview.

    Thanks for any help you can give me!

    Andrew Laverghetta

  2. #2
    Dave Parker's Avatar
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    Have you taken any pictures with it and developed them yet? you don't mention if you have actually taken pictures with the system to see how they come out on film. The diopter could have alot to do with what your preceiving in the viewfinder.

    Dave

  3. #3
    Jon Shiu's Avatar
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    Hi, just adjust the diopter so that the lines in the circle in the middle of the frame is sharp, ie point the camera at the sky is easiest. Then everything should focus properly.

    Jon
    Mendocino Coast Black and White Photography: www.jonshiu.com

  4. #4

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    It is possible that the infinity stop in the lens has moved with time. Possibly a loose screw holding the stop.
    You could check by using a piece of ground glass or frosted mylar at the film plane & check focus that way. For what it's worth infinity is considered to be 1000X the focal length of the lens. I usually just use the trees two blocks away & check for sharp branches/leaves.
    Heavily sedated for your protection.

  5. #5

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    I have shot a few rolls with it and developed maybe 3 our of 5 or 6. I have looked at the negatives with a loupe and a 50mm lens backwards and I haven't really noticed problems when I look at the negatives I haven't really noticed but I think that's largely because I haven't printed the ones where it was an issue. It does seem odd though that it stops focus so closely. When I turn the focus dial it does stop at the infinity mark though, unless the part that was mentioned is inside and not related to the scale on the outside of the lens.

    I'll see if I can check the negatives out quickly.

    One shot that I took included something in the foreground, the bank of the lake I was at plus part of the shore further away that wasn't in focus when I looked but I also stopped down to about f11 or f8 and the negative is in focus. The thing that's weird is that the split prism will just get in focus but not look like it's sharp. I guess I'll just have to shoot some more and figure it out. I didn't know if it might be a common thing or if I should have a different lens instead of the one I have now.

    Thanks for the replies so far!

    Andrew

  6. #6
    Mike Kovacs's Avatar
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    Is the focusing screen loose or upsidedown?
    If it says Zeiss or Rollei, the answer is YES!
    My Flickr Gallery

  7. #7

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    Too bad the prism doesn't come off! Then you could check the focus at both the film plane, and the viewfinder to see which one is off.

    I use a small microscope for this when repairing other cameras. http://www.radioshack.com/product/in...entPage=search

    Set it at 100x and focus on the ground glass. I also found that I can get very close with the built in magnifier of the waist level finder for many models, but the microscope is the final test. I have a ground glass out of an old TLR that I use at the film plane.

  8. #8

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    Being the econobox that it is (though still a very good econobox) the prism and all that junk can't be moved. The film is loaded with inserts and not backs/magazines so it'd be a pain in the rear to find out if the film plane image was in focus or not. I really didn't want to use part of my roll of film that I've got now to figure something out but I guess I can do that. I might just go and do that once I finish typing this. I'll shoot as close to 2.8 as possible focused to "infinity" as it says on the lens and see what comes out when I develop them. May take a while though, my next week is spoken for. Stupid college haha. Gets in the way of my creativity.

    Thanks again!

    and greg, that's one heck of a fun looking microscope for only that price! I'll have to look into that!

  9. #9
    Jon Shiu's Avatar
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    Hi, I have 2 645E's and enjoy using them. Very easy to use and a pleasure to focus. Maybe you should just call keh and send it back (or exchange it) if you are having trouble with yours?

    Jon
    Mendocino Coast Black and White Photography: www.jonshiu.com

  10. #10

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    The 1000s is also a very nice machine (just in case you do go for the exchange option). At the price of a Pro or Super, they might be willing to do an even trade for one of those.

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