Compur 1 = which board!?

[Alessandro V.]

Hello,

I've recently bought a Rodenstock 90mm f/4,5 mounted on a compur 1 shutter.
I have a Sinar X and I am looking for a proper board for this lens.
According to the seller the board should have an hole of 41.8mm to fit this shutter (he says that compur 1 it's the same thing as copal 1) but, reading some descriptions on ebay, it seems like that the board for copal 1 have different holes: 39.6, 41.5, etc...

I am sorry for the silly question but I am totally new to this and I don't know what to buy!

Thank you very much!


Ale

[BrianShaw]

Ale... not a silly question at all. An example of a problem many of us has faced until we learned that the hole sizes don't need to be all that exact. Compur 1 hole = Copal 1 hole. The bit of difference (less than 1 mm) won't make a bit of difference

I don't know what the recommended tolerances are for hole sizes, but the tolerance is fairly large. If, for some reason, the hole is tight it can be opened; if it is a bit loose the lens will generally mount with no problem and be light-tight. The only issue may be if the board has been drilled for the anti-rotation pin but the lens does not have one. My solution has been a small piece of light-proof tape (black electrical tape, but I'm sure duct tape would work too) to cover the hole.