Collinear in Compur

[alexvaras]

Hi all,

I'm going to test this lens and I could attach it to a Compur shutter, the lens its a Collinear III f7.7 N5 and the Compur is f4.5.
Checking the ground glass at max aperture with the lens, I saw less and less light stoping down the lens aperture so my guess is even with the shutter attached, the effective aperture remains f7.7, but before doing the test I wanted to ask you what do you think about this.

Thank you for any help given.
Alex

[Dan Fromm]

Alex, if the lens is mounted entirely in front of the shutter then to use it the shutter's diaphragm should be wide open and you should use the lens' diaphragm. Do not use the shutter's diaphragm to adjust exposure.

The shutter's aperture scale is for the lens sold in it, is wrong for all other lenses.

[alexvaras]

Thank you Dan.