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View Full Version : Determining Aperatures on an Unlabelled Shutter



Jeff Dyck
16-Oct-2003, 15:21
I recently purchased a "new old-stock" compur-rapid #00 shutter to replace an older problematic synchro-compur #00 I had a 65mm Super-Angulon mounted upon. The new shutter does not have a scale on it yet to indicate the aperture --> Are these shutters similiar enough that the scale is directly transferable? If not, what is the standard method for determining the aperture scale for a given shutter/lens combination?

Jeff Dyck
16-Oct-2003, 15:24
Oops - please forgive the typo in the title!

Kevin Crisp
16-Oct-2003, 16:11
Jeff: With two shutters the same size this should be pretty easy. Make sure the overall length of the two lenses when the elements are screwed into each is the same. This is particularly important with a wide angle. Measure the diameter of the aperture hole when the old shutter is at maximum aperture. This is likely wide open, or just slightly closed. Then put the new shutter to the same position with the same size hole. Transfer the metal scale (if you can) or draw on the apertures on the new lens, copying the old scale, and starting with maximum aperture lined up. Just be sure the scale is the same distance from the middle of the shutter as it was on the old one, or the arc will be different and the other f stops will be too close or too far apart. With these two extremely similar shutters, I doubt this is a problem. If you can't move the metal scale over, SKGrimes can put a scale that you know will be right on the new one for around $45.

Ernest Purdum
16-Oct-2003, 16:12
I would expect the two to be likely enough to be the same that a test roll would be a very small gamble. If not, look at my answer to Nick's 150mm G-Claron questions below.

Dan Fromm
16-Oct-2003, 17:21
If you got it from Ken Wise, check the speeds. Early this year I got an N.O.S. #00 Compur Rapid from him that he claimed was fine. The slow speeds just didn't work. Had it CLA'd by SKGrimes (more below) and not long after it came back it failed completely. Steve's heirs made it right gratis. They're good people. But I haven't bought anything more from Ken.

Also check that the cell spacing is right. I transferred a 65/8 Ilex Acugon from a #00 Opto Dynetics shutter to the #00 Compur Rapid and found that the CR was thicker. Per the late Steve Grimes, the "shoulder problem" is well known and easily fixed. But he didn't do it for free.

Cheers,

Dan

Bob Fowler
16-Oct-2003, 18:59
RE: Shutters from Ken Wise...

I've bought 3 shutters from Ken, 2 Prontor-S size 0 and a Vario size 0. All were "NOS". The first Prontor-S was perfect, as was the Vario. The second Prontor-S just needed a bit of cleaning and lube on the slow speeds escapement, but it's now working fine. Considering how inexpensive they were, I can't complain! :-)