? Anniversary Speed Graphic Focus Scales

Discussion in 'Large Format Cameras and Accessories' started by owlsplace, Jul 12, 2006.

  1. owlsplace

    owlsplace Member

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    Howdy. Just converted a 3x4 SG to pack film. I have never used one of these before and would like to find out how the tandem focus scales work. :confused: TIA, Roger
     
  2. Jim Jones

    Jim Jones Subscriber

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    Remember, the focusing scales must match the lens. Often lenses or focusing scales have been changed on old cameras. This is what an old manual says about the scales:

    The distance from the camera to the object upon which the lens is focused is indicated in feet upon a graduated focusing scale attached to the camera bed.
    Earlier models of the Speed Graphic have a pointer at the base of the lens standard, which indicates footage markings on the scale. This type of indicator is also employed when telephoto and other long-focus lenses are used. Later models were equipped with what is known as a vernier-type scale consisting of two scales closely adjoining each other: each has the same engraved markings, except that one is longer than
    the other. When the same footage numbers come opposite each other the camera is in focus for that distance.

    The very latest type of scale is a combination of both of the other types. A single set of lines and a movable indicator line is used to focus the lens on those distances which can be indicated by well-spaced lines. For those greater distances which would be indicated by very closely spaced and hard to read lines a double set of lines (vernier type) is used for quick and accurate setting of the lens. All of these footage scales have been calibrated and pre-set at the factory with great accuracy. Each camera has its own focusing scale calibrated especially for that lens with which it is furnished. Using this scale with any other lens, even of the same make, speed, and nominal focal length, may produce unsharp pictures.
     
  3. owlsplace

    owlsplace Member

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    Yes, it checks out well on the ground glass. It looks like it has the original 135mm Zeiss Tessar with matching scales. The rangefinder matches also. It should be a fun little camera...:smile: Thanks, Roger
     
  4. Dan Fromm

    Dan Fromm Member

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    Where do you get pack film? Hasn't been made for decades. Or did you mean roll film?