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  1. #31
    MattKing's Avatar
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    Quote Originally Posted by stradibarrius View Post
    So the floating adjustment is not critical like normal focus? If it is close it is good?
    Well......

    The floating element does make a difference, just not as much difference as normal focus.

    To use a hypothetical, if you have a subject that is 10 feet away, and you are off by 1 foot with the setting of the floating element (say you have the floating element set in error for 9 feet), the affect on the image is a lot less than the affect if you have the normal focus off by 1 foot (again, say you have the normal focus set in error for 9 feet).

    One thing I'm not sure of, and would appreciate knowing, is how much of the correction supplied by the floating elements relates to flatness of field.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  2. #32

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    Quote Originally Posted by MattKing View Post
    I have a 50mm floating element C lens. There is no need to refocus after you set the FLE ring.

    The ring doesn't change the focus on the lens. As I understand it, it changes how the lens corrects for aberrations and/or field curvature.
    Theoretically, it does change focus.
    Moving bits around inside the lens changes the focal length, and without changing the lens to film distance too, focus will change as well.
    But (i don't know this particular FLE lens) it may well be that the change is so small that it is less than the already small error always present in focusing, i.e. too small to be noticeable and worry about.

  3. #33

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    The floating element does indeed change focus, if you watch the focusing screen closely as you adjust it, it is visible but minimal.
    The Mamiya lens is designed to be at optimum value when the FE ring is set to the distance set on the focusing rail.
    Some might say I have a bad attitude! Too bad.

  4. #34
    stradibarrius's Avatar
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    The scale on the rail seems so imprecise??? Probably it's that I just don't really know how to use it...
    "Generalizations are made because they are generally true"
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  5. #35
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    Reviving this thread.

    I have recently become an Rb67 owner with a 90mm floating KL lens kit - and I have the question as to where do I look on the wlf to get the floating element just right - corners? Center?
    Also, if the floating element is gonna change focus, then, what ultimately is the final focusing? It should be that we get as close to perfect focus and then adjust with the floating element, right? (else we'd be on a focus adjustment loop)



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  6. #36
    MattKing's Avatar
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    Quote Originally Posted by analoguey View Post
    Reviving this thread.

    I have recently become an Rb67 owner with a 90mm floating KL lens kit - and I have the question as to where do I look on the wlf to get the floating element just right - corners? Center?
    Also, if the floating element is gonna change focus, then, what ultimately is the final focusing? It should be that we get as close to perfect focus and then adjust with the floating element, right? (else we'd be on a focus adjustment loop)



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    You cannot always see the effect of the floating element in the finder. It deals mostly with flatness of field and certain lens aberrations.

    The most accurate way to set the floating element is to pre-estimate the distance and set the floating element there.

    Then focus.

    Then check the actual distance, and adjust the floating element to that distance.

    If you are moving more quickly, focus first and then set the floating element to match.

    And if you are really in a hurry, guess the distance and leave the floating element set there while you adjust focus for each shot.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  7. #37
    analoguey's Avatar
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    Quote Originally Posted by MattKing View Post
    You cannot always see the effect of the floating element in the finder. It deals mostly with flatness of field and certain lens aberrations.

    The most accurate way to set the floating element is to pre-estimate the distance and set the floating element there.

    Then focus.

    Then check the actual distance, and adjust the floating element to that distance.

    Actual distance - you mean on the scale? Or how?

    Quote Originally Posted by MattKing View Post
    If you are moving more quickly, focus first and then set the floating element to match.

    And if you are really in a hurry, guess the distance and leave the floating element set there while you adjust focus for each shot.
    I generally have a good estimate on the distance, so after focusing I just do what you suggested above.

    But where do I get to see the effects? On print/scan?


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  8. #38
    MattKing's Avatar
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    Yes, on the scale.

    And yes, on print/scan.

    As I mentioned, a lot of the benefit is with respect to flat field performance, so if you are not shooting flat field subjects, you may not notice that benefit.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  9. #39
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    Not just flat field, but correction of aberrations that cause radial smearing in the corners. The ground glass is too low-resolution to perceive it, but the difference is quite apparent in a good print. Try a closeup composition that has sharp corner details with the adjustment set to infinity for the first frame and set correctly for the second frame. Print them both and look in the corners.

  10. #40
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    Quote Originally Posted by MattKing View Post
    Yes, on the scale.

    And yes, on print/scan.

    As I mentioned, a lot of the benefit is with respect to flat field performance, so if you are not shooting flat field subjects, you may not notice that benefit.
    I see, thank you, I'll try taking a look at my next print/scan. I am a little confused by what you refer to as flat field performance, could you explain that further?



    Quote Originally Posted by polyglot View Post
    Not just flat field, but correction of aberrations that cause radial smearing in the corners. The ground glass is too low-resolution to perceive it, but the difference is quite apparent in a good print. Try a closeup composition that has sharp corner details with the adjustment set to infinity for the first frame and set correctly for the second frame. Print them both and look in the corners.
    Ah, so is this mostly about corners then? (I'll try what you've suggested - should make for a good test!)

    Are there any mamiya or other guides around this?



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