Adjusting FSU Lenses for Leica

<p>From a lot of reading it would appear that FSU lenses were often not machined accurately, and the paired camera's rangefinders were adjusted to match the lenses at the factory. This is problematic for someone using a Leica or Canon body if you intend to use more than one lens with the body. </p>

<p>Is there a good way to adjust the length of the helical to get to Leica/Canon standard lengths? In theory a little solder and/or some careful work with a file at the right place could get things right with patience and something at infinity to focus on for calibration. Has anyone done this or is there anyone who does this professionally?</p>

<p>All you need to do is adjust the little cam that rides against the lens, then readjust the camera's rangefinder. For what it's worth, every FSU lens I've ever used on a Leica or Bessa rangefinder has focused perfectly w/o any adjustments needed. I'm sure there are some poorly made lenses that needed adjusting, I've just never run into any.</p>

<p>As Steve said, there is merely a cam adjustment, you certainly don't change the helicals. There have been lots of posts on the web about how to accomplish the cam adjustments, this one for illustration is a good straightforward one: http://www.rangefinderforum.com/forums/showpost.php?p=8589&postcount=17. Note, however, the shape of the cam itself is different from the cam on the Leicas, so there may be some compromises when using Leica lenses on FSU bodies.</p>

<p>I reread your question and understand that you are asking about FSU lenses on Leica bodies. From what I have heard (no personal experience here) depending on the year of manufacture of the lens, and the Leica body used, you may need to change the shims on the lenses ...again there is lots of guidance on how to accomplish this on the web.</p>

<p>I have had four Jupiters -- a J-3, a J-9 and two J-8s -- which did not focus correctly on Leicas. The Jupiters are copies of Zeiss lenses, and the Zeiss standard differed from the Leitz standard. There is much discussion of this matter on RFF.</p>