Archived posting to the Leica Users Group, 2012/02/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Don Goldberg did that, custom ground the cam, on my 50mm Summicron, and it is flawless now! It wasn't terribly expensive, about $80 I think. -- Chris Crawford Fine Art Photography Fort Wayne, Indiana 260-437-8990 http://www.chriscrawfordphoto.com My portfolio http://blog.chriscrawfordphoto.com My latest work! http://www.facebook.com/pages/Christopher-Crawford/48229272798 Become a fan on Facebook On 2/2/12 9:22 PM, "Vick Ko" <vick.ko at sympatico.ca> wrote: >Hmmm. Sounds like the 90AA needed a custom cam grind. I'm thinking >that it would be an expensive custom operation. > >Vick > >On 2/2/2012 9:11 PM, Henning Wulff wrote: >> Marty, >> >> This is not a focus shift issue as in - it shifts plane of focus as it >>is stopped down. This is an issue as in - it focusses accurately at one >>distance, but not at another, all at the same aperture. The 90AA >>exhibits very little focus shift, as stopping it down doesn't change the >>plane of focus much at all, at any distance. >> >> The problem with mine, and I believe Howard's, was that the cam did not >>follow the focus properly. If the lens focussed properly at infinity, it >>was off at 10m and then on again at 3m. Not very user friendly. I too >>now have some other 90 options which work better. >> >> In a related vein, the 75 Summilux exhibits focus shift in the >>traditional manner, but at f/2.8 it is off the intended focus plane by >>the same proportional amount at every distance, and I have learned to >>compensate. I can use it very well, and have a high degree of confidence >>in it. >> >> Henning >> >> > > >_______________________________________________ >Leica Users Group. >See http://leica-users.org/mailman/listinfo/lug for more information