RB67 actual image dimensions

Discussion in 'Medium Format Cameras and Accessories' started by BetterSense, Jun 2, 2011.

  1. BetterSense

    BetterSense Member

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    I don't have access to any of my RB67 negatives to measure them, but I'm trying to compare wide-angle lenses on 4x5 to their equivalents in terms of RB67 lenses. Does anyone know the length/width of the actual film gate of an RB67 back?
     
  2. Steve Smith

    Steve Smith Member

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    As luck would have it, I have an RB67 negative right here on my desk at work. The actual image size is 56mm x 69.2mm (2.21" x 2.72").


    Steve.
     
  3. Marc Akemann

    Marc Akemann Subscriber

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    56.5 mm x 68 mm (2.22" x 2.68") is what get. I measured both the film gate of my 6x7 ProS back and a recent negative.

    -Marc
     
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  4. Steve Smith

    Steve Smith Member

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    Perhaps there is some variance in the film backs then, possibly age dependent. Mine are Pro SD backs.


    Steve.
     
  5. BetterSense

    BetterSense Member

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    I need a very wide lens. It looks like my 50mm RB67 lens isn't actually any wider than the 90mm I have for 4x5. Bummer. Guess need to start looking for a 24mm for 35mm.
     
  6. EdSawyer

    EdSawyer Member

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    24mm for 35mm format is basically the same as 50mm on 6x7.

    the 37mm fisheye for the RB/RZ is the widest production lens for that system.

    Mamiya developed a 43mm aspherical rectilinear lens for the RZ back in about 2002(?) I think, but never released it, sadly.

    -Ed
     
  7. BetterSense

    BetterSense Member

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    The crazy this is that you can get 50mm (47 actually) lenses for 4x5, if you have like $2500 to spend. According to my calculations that would be like a 28mm lens on 6x7. I wonder how they pull that off?
     
  8. hpulley

    hpulley Member

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    The rear mask, rotating adapter and film back size and age determine the image size. The 6x8 adapter actually gives 56x76mm in portrait only. On a Polaroid or sheet film back you get a 76x76mm image (73x76mm on 3.25x4.25" Polaroid).

    A 17mm lens on 135 is hard to beat for wide angle but on my RB67 the 65mm lens seems wide enough for some reason.
     
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  9. fmajor

    fmajor Member

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    I'm not an expert by any stretch of the imagination, but by hubris i'll comment all the same. :tongue:

    Using a very scientifiic method - comparing view area to view area out of my window - to my eyes my 65mm lens on my RB67 is not nearly as wide as my 24mm f2.8 lens on my 35mm camera (Minolta XD-11). Maybe the Mamiya 50mm would add that extra bit of width to reach the 24mm - i have the manufacturers listed angle of view for these lenses (both Mamiya RB67 lenses and Minolta Rokkor lenses).

    To my eyes, the 65mm Mamiya is very, very close to the view of my Rokkor 35mm f2.8 lens.
     
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  10. David Brown

    David Brown Subscriber

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    I agree. On a strictly anecdotal basis, I consider my RB 65mm to be = to a 35mm on 135 film, and the RB 50mm = to the 28mm on 135.

    I always think in terms of 9/5 to compare the RB67 to a 35mm camera. The "normal" lenses are 90mm and 50mm respectively. (I know, I know, there's a zillion threads about how this is wrong.) It's all an approximation anyway, since the aspect ratios are also different.

    Discuss ... :munch:
     
  11. BetterSense

    BetterSense Member

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    When evaluating lens wideness, I always go by the long dimension, because to me, the most defining ability of a wide lens is how much horizon it can capture.
     
  12. michaelbsc

    michaelbsc Member

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    I tend to think about it this way too. I go so far as to consider the long dimension as my "normal" lend. A 35mm lens for 135, a 127mm for 4x5, etc.
     
  13. michaelbsc

    michaelbsc Member

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    Oh yeah, my 65mm is as close to 6x7 as I own.