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Thread: Closest focussing distance

  1. #1
    45-57-617
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    Closest focussing distance

    Hi,

    So I take the camera out into the backyard ...

    I have a curry leaf tree that has fronds with many leaves and berries at the extremity of the frond.

    I thought, "I wonder what those berries would look like with this lens and with that lens etc. etc?".

    I set up the camera to concentrate on a frond that extends straight towards the lens.

    When I try to get a close up photo I can see the focus coming up the frond towards me as I rack the camera out ... the rear berries are now in focus ... but ...

    Just as I think the front berries will come into focus I seem to keep extending the camera many inches and get a blur.

    For the camera position - and hence a magnification ratio - I cannot get the photo.

    So.

    I guess it makes sense and it happens with lenses in other formats too its just that I've not tried such close up photos with an LF camera.

    (BTW - I was just trying to focus at full aperture ... if aperture makes a difference at these magnification ratios then please let me know. Its dark outside now.)

    The lenses I've had a look through are a Petzval, a Xenar, a Stellor and a Heliar.

    My question, what older lenses could do 1:1? Were there any? So if one were to get into close-up (or closer up) LF photography I'm assuming one would buy a lens suited to close-up work...

    For some reason I thought all LF lenses would do 1:1 but I knew some were built for the purpose. The Stellor wouldn't do a still life of 3 pears which wasn't near 1:1 ... I thought I was going mad!

    Cheers,

    Steve

  2. #2

    Join Date
    Sep 2007
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    43

    Re: Closest focussing distance

    All lenses will focus to 1:1, some with better results than others.

    If your camera position is fixed and you're focusing with the front standard, it's quite possible that you would never achieve a focused image. Instead, focus with the rear standard (if the camera design allows it) or by moving the camera as a unit.

  3. #3
    Thalmees's Avatar
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    Jun 2006
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    Re: Closest focussing distance

    Hi Steve,
    Did not get every thing in your situation, BUT I'll share simple facts.
    Macro work @ M≥1 ranges between the following two limits:
    1) At M=1:1, Bellows Extension=Subject-Lens Distance=2F(twice focal length).
    This relationship should be satisfied for M=1:1.
    M --------------- SLD ----------------BE
    1:1 -------------- 2F ----------------2F
    2) To achieve a focused image at a Subject-Lens Distance of 1F or lesser, the Bellows Extension will be infinity(infinite extension) and not practical of course.
    M --------------- SLD ----------------BE
    ?:1 ------------- ≤1F ----------------∞
    Every Macro work(1:1 and more) will be within these two boundaries.
    From 1:1 and more Magnification, a simple displacement of subject toward the lens, will be translated in a more and more (requires)bellows extension.
    M --------------- SLD ----------------BE
    1:10 ----------- 11F ----------------1.1F
    1:1 -------------- 2F ----------------2F
    4:1 ------------ 1.25F ----------------5F
    ?:1 ------------- ≤1F -----------------∞

    Good Luck.

  4. #4
    45-57-617
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    Re: Closest focussing distance

    Thank you Thalmees,

    It looks as though I would have been case #2. The subject was not very far from my lens (less than a foot) and yet my bellows was about 450mm.

    So all lenses do 1:1 but only when the subject is twice the focal length of the lens from the lens. There you go!

    I'm going to try again. But I've learnt something today ...

    Thanks to you both.

  5. #5
    Tracy Storer's Avatar
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    Re: Closest focussing distance

    Quote Originally Posted by Steve McLevie View Post
    Just as I think the front berries will come into focus I seem to keep extending the camera many inches and get a blur.
    Sometimes, especially with close magnification, front focus misses and bypasses focusing on the desired point. Try a combo of front and rear focus in these situations, or moving the tripod back and forth may also be needed.

    Remember that "focusing" the camera by changing bellows extension is changing the magnification. If the subject and film don't move, and only the lens does, you'll only get focus by luck. (in "close-up" type shooting)
    Tracy Storer
    Mammoth Camera Company tm
    www.mammothcamera.com

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