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  1. #11

    Join Date
    Dec 2013
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    35mm
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    As promised some more photo's.
    One shows a number (2209) on the lens "mount" (I'm assuming it was screwed against a wooden plate here).
    Attached Thumbnails Attached Thumbnails DSC_0041.jpg   DSC_0036.jpg  

  2. #12

    Join Date
    Jan 2005
    Location
    Live Free or Die
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    Multi Format
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    4,559
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    It's probably a projection petzval. Given the size and weight, it probably has a pretty long focal length, and possibly enough coverage for 8x10 or bigger, as a guess.
    Point the lens out a window with a piece of white card behind it, move the card or lens until you get a focused image to estimate the focal length and image circle.
    Once you know the focal length you can calculate the lens's speed.

    One of the Mods here had a great how-to video for this, but it's not showing up for me in searches.

  3. #13

    Join Date
    Dec 2013
    Shooter
    35mm
    Posts
    4
    Quote Originally Posted by bdial View Post
    It's probably a projection petzval. Given the size and weight, it probably has a pretty long focal length, and possibly enough coverage for 8x10 or bigger, as a guess.
    Point the lens out a window with a piece of white card behind it, move the card or lens until you get a focused image to estimate the focal length and image circle.
    Once you know the focal length you can calculate the lens's speed.

    One of the Mods here had a great how-to video for this, but it's not showing up for me in searches.

    Thanks, I'll try that out this week

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