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Thread: Troubleshooting enlarger wonít focus

  1. #1

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    Troubleshooting enlarger wonít focus

    I have a customer who just got a mint condition Rodenstock Beseler APO HD 240mm f/9 enlarging lens from me. I received the following message:

    I received the Beseler 240mm lens today.

    It seems to be in excellent shape, but I cannot seem to get any kind of focus with it.
    The lens is being used in a Beseler 45 MX enlarger.
    My goal is to produce very, very small prints, and no matter how I configure the enlarger head, I cannot achieve focus.

    Can anyone help me figure out whatís going on?

    Thanks!

  2. #2
    Photographer
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    Re: Troubleshooting enlarger wonít focus

    I think that lens is too long for 4x5.
    Keith Pitman

  3. #3
    Vaughn's Avatar
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    Re: Troubleshooting enlarger wonít focus

    Perhaps needs to be on a cone of some sort to extend the focus?
    "Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China

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    Re: Troubleshooting enlarger wonít focus

    Quote Originally Posted by Keith Pitman View Post
    I think that lens is too long for 4x5.
    So you’re thinking that the head can’t get far enough away from the easel?

  5. #5
    Vaughn's Avatar
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    Re: Troubleshooting enlarger wonít focus

    The lens may not be able to get far enough away from the negative.
    "Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China

  6. #6

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    Re: Troubleshooting enlarger wonít focus

    To make a 5x4" print, the lens would need to be 500mm away from the film, and the baseboard 500mm from the lens (approximately). If they want to make even smaller prints than this, then the lens would need to be even further away from the film. So yes - sound like there's a good chance that bellows extension on the enlarger is the problem. If the user detaches the lens from the head and moves it gradually downwards, they may see the image come into focus (albeit with lots of light spill). This would confirm the problem.

  7. #7

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    Re: Troubleshooting enlarger wonít focus

    Yeah, in the good old days there were big cones for making reductions from large format negatives, huge extension tubes. Here's a Saltzman lens cone offered by glennview . That lens is a darn nice lens, nice for copy work too.

    Click image for larger version. 

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  8. #8

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    Re: Troubleshooting enlarger wonít focus

    Should have mentioned the lens cone pictured is 12 inches in length. For making reductions from 8x10 negatives.

  9. #9
    Tin Can's Avatar
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    Re: Troubleshooting enlarger wonít focus

    What size negs are they using, a 4X5 enlarger can use much smaller negs

    What size print?

    a 240mm lens needs about 19" bellows to make a 1 to 1 print

    A 35mm neg will make a 35mm print

    Reduction cones were common once

    I have a 10" cone for an Elwood, never used it

    If they want 1 to 1 prints, they can contact print...
    sin eater

  10. #10
    ic-racer's Avatar
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    Re: Troubleshooting enlarger wonít focus

    Most of the enlargers with which I am familiar that are capable of making reductions usually show or describe how to do it in the user's manual. If it is not in the manual, then it may not be possible. But this is how to do it.

    The enlarger needs a lot of bellows draw. Once in the correct orientation, moving the head up makes the image smaller. If this is not the case, then it is not setup correctly.

    Focal length selection when making reductions is based on the diagonal of the print not the negative. So if making 4x5" reductions from 8x10" negative, don't use a 300mm lens, use a 150mm lens.

    Since the lens will be very close to the paper, most enlargers will not be able to do this without propping the easel up on a box of some sort (not shown in the pictures below.)

    In my darkroom reversing the lens is not needed when making prints due to the low resolution of printing paper and, of course, the small size of the prints.

    If making copy negatives that will be enlarged, reversing the lens might improve results at the corners.

    1:1 printing setup is similar. In that case for 8x10" negative a 210mm lens works best in my darkroom (specs on my 210mm lens show it covers 11"x11" at 1:1).



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