Archived posting to the Leica Users Group, 2008/10/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Correct (sort of) I'm not sure if I'm using the term "back focus" properly In straight RF mode; using the lens with the M focusing tube (with cam): Focusing with the RF on an object at a distance of six feet the actual focus occurs about 5.5" in front of the object. In other words: in order to get the desired object in focus one must focus "behind" that object (shorten the tube). as far as the lens tube = too short no, in this case = too long however, I don't see it quite that way - just too confusing. It's really a matter of the cam giving false information to the RF. The cam needs to be adjusted to link accurately to the RF. Fond regards, George george@imagist.com http://www.imagist.com http://www.imagist.com/blog http://www.linkedin.com/in/imagist On Oct 18, 2008, at 9:08 AM, Frank Filippone wrote: > Is this correct? > > In "straight " RF mode the lens back focuses...... > Using a Visoflex, focus is correct.... > > Back focus = the focus "tube" is too short (?) making the focal > plane at > infinity behind the sensor plane? > > Did I get all the conditions right? > > Frank Filippone > red735i@earthlink.net > > > Works beautifully with the Viso III. > Severe back focus without it. > > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information