Taking Versus Enlarging Lenses for Macro Photography

Discussion in 'Photography Chat' started by dddiver, Apr 13, 2008.

  1. dddiver

    dddiver

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    Hi all,

    I am building a special purpose digital (APS-c) macro camera and need to decide between using enlarging or taking lenses. The focus and apertures will be fixed and the apertures will be very small (estimated F32-90). There will be a certain unavoidable loss of sharpness due to bending of light along the rims of the apertures. I am wondering if this problem will be any worse with enlarging lenses? The reason I suspect loss of sharpness will be worse with the enlarging lenses is that I've read the following:

    All enlarging lenses should be used at the widest stop that minimizes aberrations, since diffraction is a far, far worse problem in enlarging than it is in taking lenses. (There is a good article on exactly why by Ronald B.J. Wisner in a back issue of D&CCT).

    You should never stop down a 50mm enlarging lens to f/8 or, worse, f/11.
    If you don't believe this, simply get a very good grain magnifier and a
    negative with crisp grain and WATCH the image of the grain as you stop
    down. Stop down a few clicks and watch the grain magically get sharper,
    then continue stopping down and watch it get mushy again. With virtually
    all lenses there is a quite clear optimum--and it is this aperture that
    you should always use for the sharpest prints
    .”

    So my question is, knowing the apertures will be very small, and assuming for the sake of discussion that all other factors were equal (of course they will not be), will I experience more distortion with the enlarging lenses due to their design biased towards use at wider apertures?

    In case it is relevant, I'd probably use 6 element coated enlarging lenses of 60, 80 and 105mm. They work becasue i do not need any focus and I need relatively small lens diameters. If I use taking lenses, I'll probably need to use MF TLR lenses to get the small diameters needed. But if anyone can suggest some small diamter (e.g., 39mmm or less) true macro taking lenses, I would be grateful.

    Also, does any one have access to the article by Ronald B.J. Wisner in a back issue of D&CCT?

    Many thanks,
    dddiver
     
    dddiver, Apr 13, 2008
    #1
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