Which diopter for RB67

Discussion in 'Medium Format Cameras and Accessories' started by Doc W, Oct 18, 2010.

  1. Doc W

    Doc W Subscriber

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    My eyes are getting older and I need a new diopter for my RB67. I read that Mamiya will send you the whole set with a 10 day return so you can pick the one you need and send back the rest. However, that doesn't seem to apply in Canada. Vistek knew nothing about it and they are the Mamiya distributor.

    So, how do I tell which diopter I need?
     
  2. mwdake

    mwdake Member

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    Do you wear glasses?
    If so ask your eye doctor for the diopter strength.
    Or take your glasses to where you got them from and ask them to measure them; they have a gizmo to measure the strength of the lenses.
     
  3. Doc W

    Doc W Subscriber

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    I tried using different reading glasses to no avail. I took the diopter from the camera to the optician and he said it is 11.5, whatever that means. The Mamiya diopter set for farsighted eyes has -1.5 as standard and then a +1 and 0 but I have no idea what that means.

    Does anyone have experience with Mamiya diopters?
     
  4. fmajor

    fmajor Member

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    Ummm, stupid question here...

    How do you tell which diopter is installed on your camera?

    I've looked at mine, but see no numbers regarding +/- anything...
     
  5. Doc W

    Doc W Subscriber

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    I also found nothing. The optician measured it on some device.
     
  6. MattKing

    MattKing Subscriber

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    Are you talking about diopters for a prism finder or a focusing hood or a waist level finder?

    Here is a chart with information about the choices available, although I think it is in error with respect to the focussing hoods - three +3 diopters?

    EDIT: The manual for the Pro-S includes the following information:

    "* In addition to the standard (-1.3) diopter lens, available are +1, 0, -1, - 2, and -3 diopter lenses (six in total]."
     

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  7. mwdake

    mwdake Member

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    Sometimes they are marked in very small text; other than that the only other way to tell is to have it measured.
    I have a -1.5 for the RB Waist Level finder that is clearly marked on the plastic surround in white text as -1.5; but I have a second one that is supposed to be -1 that does not have any markings. If you are talking about a diopter for the prism type finders that do not have a plastic surround but just a piece of glass or plastic they are typically marked with dots on the side of the glass to indicate their strength; I have one with 2 red marks on the side and is supposed to be -2 and I guess they may use some other color to indicate + diopter?


    Basically a diopter measurement is a measurement of the power of a lens and is the reciprocal of the focal length in meters.
    It basically moves the focus forward or backwards in oder to correct for your eyesight.
    Negative diopters are for people who are nearsighted and positive ones for people who are farsighted.

    Reading glasses are typically positive diopters.
    I don't think I have have ever heard of a camera diopter lens of 11.5; I think that measurement may be in arc minutes.
    Maybe there are some optometrist folks on apug that can go in to more depth or correct me if I got something wrong.
     
  8. Doc W

    Doc W Subscriber

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    I have the waist level finder. I also think we need some APUG optometrists to wade in here. I don't understand the relationship between the measurement made by the optometrist and the diopter strengths listed by Mamiya.