Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: studio347 on November 27, 2012, 04:32:58 pm

Title: function of metal ring in a copal shutter
Post by: studio347 on November 27, 2012, 04:32:58 pm
Hi,
What's the function of thin metal ring which is placed between a copal shutter and the front glass?
I find one yellow color ring at a schneider lens and 3 black rings(together combined) at a rodenstock lens.
Can I use the lens without the ring(s)?
Thanks in advance!
Title: Re: function of metal ring in a copal shutter
Post by: Ellis Vener on November 28, 2012, 08:40:13 am
they are shims installed by the lens maker to create the correct spacing between  the front and rear sets of elements for the individual shutter the sets are installed in. For best optical performance leave them installed.