Mounting lenses in different shuttersgreenspun.com : LUSENET : Large format photography : One Thread
I want to buy Copal press shutters to replace my standard Copals for my Schneider SA 90 and my Nikon 210 (Copal 0 and 1). I remember reading somewhere some years ago that each shutter was perfectly matched to each lens, and installing a new one wasn't simply a matter of unscrewing from one and screwing into another; that some sort of precise spacing calibration had to be done. I called a well-respected camera repair place in NY that I figured would do such work, and they didn't seem to know what I was talking about. I then searched here, and elswhere on the web, and couldn't find anything on the subject.
Did I just imagine reading this? Can I simply install the lenses in the new same-brand/size shutters and go on my way, or are the optics compromised if they aren't calibrated perfectly, however that's done. If so, where do I get this done, and what might it cost?
Thanks for any help!
-- David Brennan (firstname.lastname@example.org), February 19, 2002
SK Grimes is the man you want to talk to
-- Wayne (email@example.com), February 20, 2002.
My understanding is that modern shutters are made to sufficient accuracy that they are interchangable. This is the typical approach of mass production. The brochure that comes with Copal shutters gives accuracy specifications, e.g., the thickness is controlled to 0.025 mm = 0.001 inch. I imagine that lens designers take these tolerances into account so that lenses don't have to be custom fit to particular shutters. I have seen adjusting shims or machining to adjust the spacing on wide-angle type lenses such as the various Super-Angulon, Grandagon, Nikkor-SW. In this case I think manufacturing variations in the focal lengths of the components are being taken care of, not of the shutter.
The short answer is that you should be able to remove lens components from one Copal shutter and place them into another. Just don't lose any shims that might be present.
If you want to be absolutely sure that the transplant is ok, either conduct before and after photographic tests, or have a machine shop measure the total length of the lens in the old and new shutters.
-- Michael Briggs (MichaelBriggs@earthlink.net), February 20, 2002.
Spacing IS necessary in many cases, but the primary concern is the F/stops on the shutter.
Many lenses use identical shutters, but due to their actual dimensions the f/stops vary. An f/5.6 on one lens may not be the same diameter as on another.
It is based on focal length and diameter.
In most cases, a new scale will be needed on the new shutter.
-- Matt O. (firstname.lastname@example.org), February 20, 2002.
I would have a pro do it for you and the only one that I would trust is Steve Grimes in Rhode Island! This is one of the things he does all the time. You can find him on the board once in a while but he does have a web site. Cheers
-- Scott Walton (email@example.com), February 20, 2002.
Yes, this switch to Press shutters can be readily done. Sometimes wide angle lenses need extra attention to be sure the iris is in the right place and the setup of spacers allows iris operation. I do this work.
In New York City I have a good relationship with Louis Shu of Photo Gizzmo on Christopher St. Call or visit him, I'm sure you'll find him familiar with all this. 212-463-0130
-- Steve Grimes (firstname.lastname@example.org), February 20, 2002.
Thanks to everyone for your responses. I forgot about the aperture calibration. I'm going to contact Steve Grimes to have this done.
-- David Brennan (email@example.com), February 20, 2002.