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Push On Filter Design

BobUK

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Oct 13, 2021
Messages
612
Location
England, UK
Format
Medium Format
Some of my vintage cameras have no filter thread on the lens, so push on filters have to be used.
Most of the filter mounts have a notch machined into the edge.


What is the purpose of the notch?

Thank you.
 

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My Goerz Tenax needs it because the speed setting dial on the shutter is too close to the lens, and many front element focusing lenses have a peg that stops the focusing ring from going past infinity (and the closest focus).
 
Some front cell focussing lenses have a protruding lug that stops focus at Infinity, and closest focussing, with a pin stop in the shutter.. So as JPD says

Ian
 
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