Enlarger lens aperture

Discussion in 'UK Photography' started by Paul Giverin, Jun 8, 2009.

  1. Paul Giverin

    Paul Giverin Guest

    What is the purpose of variable aperture in an enlarger lens? I've been
    told that using a smaller aperture allows for a longer exposure which in
    turn gives you more scope for dodging and burning.

    If that is true, I'm sure there must be some sort of trade off with
    using a smaller aperture. I'm guessing that a larger aperture will give
    a sharper image but I'm hoping that someone can give me a definitive
    answer.

    I'm looking at enlarger lenses on ebay and I see that Nikkor do a 50mm
    in f2.8 and f4. The f4 seems to sell for less than the f2.8, hence all
    the questions.

    TIA,

    --
    Paul Giverin

    British Jet Engine Website:- www.britjet.co.uk

    My photos:- www.pbase.com/vendee
     
    Paul Giverin, Jun 8, 2009
    #1
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  2. Large aperture enables the details to be examined and the focus to be
    set accurately, then the lens can be stopped down for the actual
    exposure.

    IIRC the best range of exposures is around 20-30 secs to allow for
    dodging and burning accurately.

    Mike
    --
    Michael J Davis

    Now with added pictures on http://www.flickr.com/photos/watchman

    <><
    The camera is an instrument that teaches people how to see without a camera.
    Dorethea Lange
    <><
     
    Michael J Davis, Jun 8, 2009
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  3. Paul Giverin

    Rob Morley Guest

    Not just for fancy stuff - if you have a longish exposure it's easier
    to time it accurately and tweak it precisely than with a short
    exposure, especially if you're doing it manually.
    Using a lens on full aperture can lead to the image being a bit soft
    or distorted around the edges, just as with a camera lens.
    ISTR those are two totally different lens designs, one with four
    elements and the other with six, though I could be wrong. The slower
    one should be fine to get you going, and might be all you ever need if
    you're not planning to do large colour prints.
     
    Rob Morley, Jun 9, 2009
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