I have a super-angulon 90mm 1:8 lens and the shutter (copal0) stopped working. I also have a spare copal0 5.6 shutter. My question is, if a put the cells into the 5.6 shutter, how far off will my actual f stops be?
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I have a super-angulon 90mm 1:8 lens and the shutter (copal0) stopped working. I also have a spare copal0 5.6 shutter. My question is, if a put the cells into the 5.6 shutter, how far off will my actual f stops be?
They are mechanicaly the exact same shutter. Hopefully If you swap the F stop scale everything should line up just fine.Quote:
Originally Posted by rich caramadre
My mistake. They are both synchro-compur shutters. The original one is 8 thru 64. The replacement one is 5.6 thru 45. The f stop scale is printed directly onto the shutter. So I can't switch them. If these are mechanically the same dose that mean 5.6 on the replacement shutter would really be 8 for my lens cells?
because different lenses have different designs, you probably can't tell if they both start their scales at the same physical aperture size
Jon
Shouldn't it be possible to simply swap the front plate between the two shutters? At that point wouldn't everything work as it should?
Dan
Yes that should work just fine. But I would have him use a local repair person. The speed ring on those can come off and there are a couple of springs that might come out of their retaining groove.Quote:
Originally Posted by Fotoguy20d
Hi Rich !
You can swap the shutters and check with the new one thar 'new 5.6' actually (or not !) corresponds to the max aperture of the lens, the one that was labeled '8' with the previous shutter.
If the shutter is exactly the same, i.e. the controls of the iris blades are exactly the same from a mechanical point of view, only the labels & engravings change, hence, the probability that "new 5;6" reads "actual 8", etc ... and "new 45" is "actual 64" is very high .. but has to be checked.
Probably your Compur shutter does not have equidistant f-stop engravings like modern shutters, but it is easy to check whether "new 5;6" corresponds to "old 8' and so on.
Personally I would have more concern about retaning the initial lens sharpness: be careful when you unscrew the front cell, if a tiny & very thin spacer ring comes off, keep it preciously and re-install it back at the same place on the new shutter.
If no spacer ring is found probably you can probably swap shutters safely yourself without much concern.
So here is what I did. I set both shutters on on the table and put them on f16. I could see opening on the old (jammed) shutter wass a bit bigger than the new one. I opened the new one up a half a stop (f11 1/2) and it matched the old one. At least to my eye. I shot a few sheets of e6 and they looked good. Luckily I work at a lab so I can process my film quickly. So for now I'm going with opening up a half stop. Just one more think to remember out in the field.
Rich