Mounting lenses in different shutters

[david_brennan]

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.

 

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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?

 

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Thanks for any help!

 

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Dave Brennan

[wayne__]

SK Grimes is the man you want to talk to

 

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http://www.skgrimes.com/

[michael_briggs2]

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.

 

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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.

 

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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.

[matt_oulman]

Dave -<BR>

<BR>

Spacing IS necessary in many cases, but the primary concern is the

F/stops on the shutter.<BR>

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. <BR>

It is based on focal length and diameter. <BR>

In most cases, a new scale will be needed on the new shutter.

[scott_walton2]

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

[s.k. grimes inc]

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.

 

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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

 

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<a href="http://www.skgrimes.com/">Steve Grimes </a>

[david_brennan]

Thanks to everyone for your responses. I forgot about the aperture

calibration. I'm going to contact Steve Grimes to have this done.

 

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Dave