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Thread: Waterhouse Stops: DIY Tips

  1. #11
    Mark Sawyer's Avatar
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    Re: Waterhouse Stops: DIY Tips

    Stick a thin ruler inside the Waterhouse slot, and measure the desired diameter with a second ruler through the front element.
    "I love my Verito lens, but I always have to sharpen everything in Photoshop..."

  2. #12
    Drew Bedo's Avatar
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    Re: Waterhouse Stops: DIY Tips

    I was going to start with hand-cut heavy card stock till something fit right. Compass, Ruler and scissors I can handle. This will help get the inner diameter for the curved part at top and bottom, and the width of the straight sides. When the paper prototype is right, I'll go to a machinest I know and try to get him to make one to see how close it is. Eventually, the part will be "right" and I can fool around with getting the apertures right. If I can bring this project forward, I try to get some pictures posted here.
    Drew Bedo
    www.quietlightphoto.com
    http://www.artsyhome.com/author/drew-bedo




    There are only three types of mounting flanges; too big, too small and wrong thread!

  3. #13

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    Re: Waterhouse Stops: DIY Tips

    Quote Originally Posted by Drew Bedo View Post
    Unless I am totally mistaken, that is essentially true.

    I intend to first determine the open aperture of the lens without a stop inserted. Then physically measure the diameter inside and calculate the area. Then calculate the diameter of an opening with half that. This will be the first insurable stop. Tthis will be repeted for the other smaller stops.
    just figure out the max diameter for your stops and divide it by 1.4, 2, 2.8, etc. to get 1 stop increments, then multiply the lens's f/stop by the same amount to get the f/stop of each stop.

  4. #14
    Drew Bedo's Avatar
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    Re: Waterhouse Stops: DIY Tips

    Quote Originally Posted by maltfalc View Post
    just figure out the max diameter for your stops and divide it by 1.4, 2, 2.8, etc. to get 1 stop increments, then multiply the lens's f/stop by the same amount to get the f/stop of each stop.

    What I did do:

    • Measured the entrance pupil as viewed from the front, as advised elsewhere in thread.
    • Determined the back-focus/focal length by mounting the lens to a camera and focusing at infinity. This dimension measured from stop slot to GG.
    • Hand-cut a piece of heavy card stock to fit the stop slot. Removed the front elements and drew a circle on the card "stop", directly tracing the physical aperture. This was then measured from the outside of the mark.
    • This measurement was taken as the physical dimension of the wide-open aperture.
    • The area of that circle was calculated using the classic formula, Pi x r squared.
    • Subsequent full-stop dimensions were then calculated in descending sequence.

    Then
    I did pretty much what you have suggested to check my calculations.

    Now I will have to get some of these fabricated from brass.
    Drew Bedo
    www.quietlightphoto.com
    http://www.artsyhome.com/author/drew-bedo




    There are only three types of mounting flanges; too big, too small and wrong thread!

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