Archived posting to the Leica Users Group, 2003/01/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Austin, Henning is completely right. His explanation in his previous email was clear and technically correct. In a flat-field lens the edge of frame is focussed at a farther distance than the center of frame. Therefore if you focus using the center of frame, and then reframe, the lens will not be exactly focused on the subject. If you want I can draw a diagram tomorrow. JB On Tuesday, January 14, 2003, at 09:49 PM, Austin Franklin wrote: > Johnny, > >>> The plane of focus is an arc with the "anchor" point at the center of >>> the >>> film plane, and the radius the distance to the subject. As long as >>> you KNOW >>> that and use that to focus, there is NO changing of focus to >>> accommodate >>> this. >> >> actually that is not true, Austin. > > I certainly didn't use very good terminology. But, with respect to > what I > was talking about it is true. - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html