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Thread: Making DIY aperture scale for Prontor Prof. Sshutter

  1. #1

    Join Date
    Mar 2014
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    Hemmingen, Germany
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    147

    Making DIY aperture scale for Prontor Prof. Sshutter

    Hey folks!

    I need a short hint how to do this. I whant to Mount a Rodenstock APO Ronar 300mm/9 into a Prontor Prof. 1S shutter. The shutters aperture scale starts from 5,6 onwards. But the Prontors have clicks in 1/3 f-stops. Normaly I would think that I start at 9 and count onwards to 11, 16...but is this really correct? It is annoying me that the first step from 9 to 11 is only a 2/3 step!

    Any suggestions are welcome!

    Sebastian

  2. #2

    Join Date
    Mar 2014
    Location
    Hemmingen, Germany
    Posts
    147

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    Now I found the information that the stops (and clicks???) are adjusted by two screws on the back of the shutter. So unfortunately it wont't be as easy as I hoped. At least I found a photograph of exact this lens in this shutter and it seems if the same number of stops is done in nearly the same overall stoppig-distance

    https://grossformatfotografie.de/thr...1-9-300-mm-mc/

  3. #3

    Join Date
    Sep 1998
    Posts
    10,313

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    Why not call Rodenstock and ask them if they still have scales left?

  4. #4

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    I have had similar problems when using old shutters from 120 bellows cameras with homemade lenses on a 4x5 camera. The aperture readings of the shutters bears no resemblance to the amount of light entering the camera. The solution i devised is written up in another blog on this site entitled "through the lens metering"

    Sent from my SM-T210 using Tapatalk

  5. #5

    Join Date
    Jul 2016
    Posts
    1,133

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    Quote Originally Posted by sdzsdz View Post
    Hey folks!

    I need a short hint how to do this. I whant to Mount a Rodenstock APO Ronar 300mm/9 into a Prontor Prof. 1S shutter. The shutters aperture scale starts from 5,6 onwards. But the Prontors have clicks in 1/3 f-stops. Normaly I would think that I start at 9 and count onwards to 11, 16...but is this really correct? It is annoying me that the first step from 9 to 11 is only a 2/3 step!

    Any suggestions are welcome!

    Sebastian
    I solved same by printing a vynil sticker, if IIRC cost was 1€.

  6. #6

    Join Date
    Mar 2002
    Location
    St Paul Mn
    Posts
    80

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    300mm is close enough for rock and roll (assuming b&w) to 12". Use a caliper to measure the aperture, setting it to open one inch. This is f12. Work out the offsets.
    Last edited by Brook Martin; 26-Sep-2017 at 20:20. Reason: grammer

  7. #7

    Join Date
    Jun 2004
    Location
    Melbourne, Australia
    Posts
    507

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    If you still have the original shutter (or barrel) for the APO Ronar the all you need to do is measure the diameter of the aperture at each marked f stop. This measurement will be the same for the new shutter at the same f stop.

  8. #8

    Re: Making DIY aperture scale for Prontor Prof. Sshutter

    Paul, that makes sense except the shutter aperture has fewer blades so measurement won't be precise (irregular hole). However, that may not matter enough to be concerned with. 'Close enough' is often close enough... just not something we OCD folks are comfortable with.

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