Using elements from Sinar DB mount

[Terrance Hounsell]

If the lens elements are removed from a Sinar DB mount and fitted into the appropriate size Copal shutter will the nodal points be properly spaced to ensure sharp focus? (Thanks for your help)

 

[freygr]

If the Sinar DB mount and the Copal shutter are the same thickness the image will be the same sharpness as before. The only problem would be if the Copal shutter is thicker than the Sinar DB mount. You can shim or use spacers to make the shutter thicker to match the Sinar DB mount spacing but not the other way.

If you moving the lens elements due to needing a larger lens board, you can always make any adapter lens board which will mount the Sinar DB mount.

 

[Terrance Hounsell]

DB mounts same thickness as Copal Shutters?

I should have been more specific in my question. I have mounted several barrel lenses into shutters in the past so I am aware of how/what needs to be done. The specific question is "Are Sinar DB mounts the same thickness as the corresponding Copal Shutters". The reason for asking is that I am trying to determine if the elements can be swaped directly and focus correctly without making any alterations. Thanks.

 

[Tom Stanworth]

I once bought a Rodenstock 75 f4.5 in a Copal 0 that was 'funny' unscrewing the front assembly resulted in it coming undone after 1/4 turn and falling away from the shutter. The casing was such that the assembly pressed on the front of the shutter and instead of screwing home, pressed on the dial face and as it was tightened instead of coming to a halt, prevented teh speed dial turning. Therefore the assembly was entirely different. I can only assume that as the front did not properly screw into a copal 0 (correct shutter) that it was DB and therefore had an entirely different external geometry. Needless to say I returned it!!!! this is the only case of what I thought to be a DB lens/copal situation that I have encountered and there is no way that lens could have been used in a regular shutter.

 

[davekarp]

I purchased the cells from both a Grandagon N 90mm f/4.5 and 75mm f/4.5 that had formerly been mounted on a DB shutter. They both reside on Copal shutters, and no adjustment was necessary to make this work. The cells screwed right into the shutter with no problem.