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  1. #1
    Steve Smith's Avatar
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    A question for owners of 4x5 enlargers

    For a while now I have been thinking about building a 4x5 enlarger.

    To save a lot of trial and error and perhaps some complex calculations, I would appreciate it if someone could help me out by measuring the distance from the negative to the lens board at both minimum and maximum bellows extension on a standard 4x5 enlarger.

    Thanks.



    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #2

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    Omega DII
    max 9.5 (243), min 4.25 (108), Including depth of lens cone which is 2.5 (64)

    LPL 4500
    Min 2.5 (64), max 9.5 (243) , including depth of the lensboard which is .75 (20)

    Measurements are inches and (mm), and are made from the negative stage to the lens mount surface.

  3. #3
    Steve Smith's Avatar
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    Thanks. That's exactly what I wanted.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  4. #4
    Bob F.'s Avatar
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    Durst L1200. Min 40mm, max 240mm; negative to lens panel (give or take a couple of mm). I seem to get away without a recessed panel with a 50mm lens for 135, but others have found them necessary.

    Have fun! Bob.

  5. #5

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    I found that with my Beseler 45 the minimum distance is a bit too long for 35mm format. I have to get the bellow to compress quite tight to focus correctly with most magnification.

  6. #6

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    Steve, I am at work now, so I can't measure my two Beseler 45s (one with the Ilford MG600 head, one with the Condenser Head), but an observation:

    When I use the one with the Ilford MG600 head, with 35mm, I am often at minimum extension - so much so that I have considered making a recessed lensboard for my 50mm lens. I rarely find that I need to use the maximum bellows extension, since I rarely print really small, and when I do, it is usually not with 4x5 negs, so I can always get a smaller image with a more convenient enlarger head height by using a longer lens.

    You can calculate the maximum bellows extension required too, if the distance between the negative and the optical center of the lens is B, and the distance between the center of the lens and the easel is E, then the magnification is E/B and if the focal length of your lens is F, then when in focus, 1/B + 1/E = 1/F all of which means that if the smallest print you want to make is a 1:1 size print, then the maximum bellows extension is approx 2X the lens focal length. The shortest bellows extension would come about with an infinite sized print, at which point the bellows extension is equal to the lens focal length.

  7. #7
    Jim Jones's Avatar
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    On my old 4x5 DeJur the minimum is about 3.5 inches and the maximum about 9.1 inches. That long minimum means a lens board recessed 1.6 inch and a 3.5 spacer above the film to focus the condenser are required for 50mm lenses.

  8. #8

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    The focal length of the lens is going to make a difference in the distance. In bdail's post, I'm assuming the measured distance for the DII is for a 135mm lens, based on the 2.5 inch cone. A 150mm lens takes the 4 inch cone.

  9. #9
    dpurdy's Avatar
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    Interesting. I use a Beseler 45 mxt and I have no problem focusing with a 50mm lens even at the largest enlargement. Mine is a grey one from the 60s. Perhaps they tried to cut some corners in the later models.

  10. #10

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    Might depend on which 50mm you are using. Some will have different flange focal distances. My CB-7 is pretty tight with the Nikon 2.8. My memory tells me other brands would need more space so would have no problem. Beseler sells [or used to] a recessed board and I think it was specced for the Nikon 50mm F2.8.

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