I say its EASIER to focus longer lenses with the same accuracy at same fstop/speed, all else being equal. jco
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Cory Papenfuss Sent: Tuesday, November 14, 2006 2:46 PM To: Pentax-Discuss Mail List Subject: Re: Using a Super Tak w/ istDS- A challange to the list? > So, how does one measure ease of focusing in a lab? How does one > measure comparative ease of focusing (say a 35mm lens v a 105mm lens)? > What tests are used, what equipment is used? How do you define > "ease?" Is the lens tested on a camera, or is the camera something > that gets in the way of an objective test? Is there an "easy of > focusing" machine to which the lens is attached? Do you use more than > one sample of each lens? Do you change the light at times, vary the > subject? Is there an "ease of focusing" test target? How does the > target relate to real world subjects? For example, does the lab > target have a face? A nose? Eyes? Wear glasses? Or is it some flat > sheet of paper with grid lines on it? > > Shel > > Again... I believe I was careful not to say, "ease," but rather "accuracy." The latter can be objectively measured and quantified and the former will always be run through an individuals' personal preferences. -Cory -- ************************************************************************ * * Cory Papenfuss, Ph.D., PPSEL-IA * * Electrical Engineering * * Virginia Polytechnic Institute and State University * ************************************************************************ * -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
