process lens and how to ID them ?

Discussion in 'Darkroom Equipment' started by ac12, Mar 17, 2013.

  1. ac12

    ac12 Member

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    I've read some of the threads about process vs. enlarging lens, and understand that I should NOT get a process lenses.
    But on the used market, how do I tell what is a process lens from an enlarging lens?

    I got more confused when I read a post that said that the Rodenstock Rodagon was available in BOTH process and enlarging lens. So that post told me that I could not even depend on the name Rodagon to be an enlarging lens, I could accidentally purchase a Rodagon process lens thinking it was a Rodagon enlarging lens.
    Are there any visual clues on the lenses of the different brands to indicate enlarging vs. process?

    For enlarging, I am limited to printing 16x20 or slightly larger. So no large magnification requirement. 4x5 will be max 5.5x enlargement and 6x6 will be max 11.5x enlargement.
    I am looking first for a 135 (4x5) and next for a 105 (6x9) lens.
    And for now, because of lack of budget, I will not be looking at APO lenses. Unless someone offers me a godfather deal.

    This pix is an example of what I found on eBay.
    The left lens looks like an old lens that I used to use in high school.
    The middle lens I have never seen before. Is it a process lens?
    The right lens looks like the current enlarging lens.

    thanks
     

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  2. richard ide

    richard ide Member

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    IMO whoever told you not to use a process lens was badly misinformed. Process lenses are ideal for enlarging as they are designed to photograph flat objects and are apochromatic. Commercially I have used process lenses from 240mm to 1200mm focal length for enlarging. One difference is the reproduction ratio range that the lens is optimized for. Process lenses are commonly used for magnifications from 1:1 to 1:3 but will do an amazing job outside that range. Different lens designs will be optimized for various magnification ranges.
    Buy the 135mm lens first. Test a 6 x 9 negative with it and you might not need a 105mm depending on you enlarger and setup.
    Your middle lens is an enlarging lens. It could be used as a process lens but it only has a 50mm focal length so would be totally impractical to use as such.
    Have fun.
     
  3. AgX

    AgX Member

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    The Apo-Rodagon is considered by Rodenstock as repro-, the Rodagon as enlarging-lens.

    Amongst repro- and enlarging lenses is a variation between angle-of-view and speed. Thus these features cannot be used to dived them.

    The only golden-thread would be the scale dependancy:

    Repro-lenses are designed for scales including 1/1, whereas enlarging lenses exclude 1/1
     
    Last edited by a moderator: Mar 17, 2013
  4. brucemuir

    brucemuir Member

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    If you go used make sure they throw in "jam nut" (threads on the lens and holds it against the lensboard) which is usually M39 so you can mount it right up without hitting an additional stumbling block.

    You have an enlarger, correct?
    Do you have a lensboard yet?
     
  5. MattKing

    MattKing Subscriber

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    All the lenses you have pictured are enlarging lenses.

    If a lens has features like illuminated f/stops and the ability to easily switch between a set aperture setting and full aperture, it is almost certainly an enlarging lens.

    Correct me if I am wrong, but I believe a fair percentage of process lenses don't have or need variable apertures.
     
  6. ac12

    ac12 Member

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    Thanks guys.

    Bruce
    I have the enlargers (Omega D5 and Durst L1000) and lensboards (as long as the lens has a 39mm mounting thread), I even have extra 39mm retaining rings.
    I know what you mean, I had some lens w/o retaining rings and w/o the retaining rings I could not mount them. So I picked up a few, for my lenses and to keep a spare on hand.
    The only stumbling is if I run into a Schneider Componon-S 135mm with a 42mm mounting thread. I don't have a lensboard for that lens.
     
  7. Huub

    Huub Member

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    The Rodenstock 135 mm Rodagon has 39 mm and is an excelent enlarging lens for 4x5.