Copal 0 shutter f/4.5 and f/5.6 ..?

[Torsten]

Hi, could someone please tell me if only the marking/labeling changes between the two, or also the true inner aperture of the shutter (that's what I fear)? In other words,
what happens if I put a Copal 0 "f/5.6" betwenn two 90/4.5 lens elements?

thank's

Torsten

[Ernest Purdum]

No problem. Copal 0 shutters have all the same opening when they leave the factory. Differing diaphragm markings are added for whatever lens cells are to be installed.

[Torsten]

thank's for the info!!

cheers
Torsten

[Jim Galli]

Hi, could someone please tell me if only the marking/labeling changes between the two, or also the true inner aperture of the shutter (that's what I fear)? In other words,
what happens if I put a Copal 0 "f/5.6" betwenn two 90/4.5 lens elements?

thank's

Torsten

Couple of things to consider. The f5.6 scale will only be good for whatever was in it before. If it had 150 f5.6, that won't work for 90mm cells. Also if I'm not mistaken there aren't any 90mm f4.5 cells that fit a Copal 0. They all seem to be Copal 1. I'm thinking of wide angle 90's for 4X5 of course. There may well have been some old 6X9 folders that had a 90mm f4.5 tessar or something.

Consider f10 for both a 150mm lens and a 90mm lens. f10 for the 150 needs a 15mm hole. f10 for the 90 needs a 9mm hole. So the scale can say anything and it won't necessarily match the cells unless they were a matched factory set to begin with.

[eddie]

good point jim,

but once we find the correct f stop value then we could still use the scales as the values still represent 1/2 or double....am i thinking of this correctly?

[Bob Salomon]

good point jim,

but once we find the correct f stop value then we could still use the scales as the values still represent 1/2 or double....am i thinking of this correctly?

No, just get a pair of blank scales, either from the Copal distributor (each Copal shutter sold by the factory that will be sold as a shutter only comes with both scales already screwed on). Any camera repairman can calibrate and mark the scales or you can try to do it yourself.

[Jim Galli]

good point jim,

but once we find the correct f stop value then we could still use the scales as the values still represent 1/2 or double....am i thinking of this correctly?

You could do that but it's a lot of mental gymnastics and ultimately you'll go the opposite direction or some such, and Murphy says it will always be your most important shot. One approach I'm guilty of is to flip the scale over to the blank side and "etch" the new numbers in. One nice thing about modern shutters over old is the numbers are all evenly spaced. So when you've found f8 the rest are equi distant one side and the other.