Hi, > Perhaps a better test would have been to focus on a one dimensional > object
is there such a thing? How would we see it? <g> --- Bob mailto:[EMAIL PROTECTED] Sunday, March 24, 2002, 2:58:55 PM, you wrote: > I made some critical focusing tests at one time, using a 105mm lens @ > f/5.6 on the LX with the refconverter M, which allows for 2X > magnification. With the camera on a tripod, I very carefully focused on > the eyes of a nearby piece of sculpture from a distance of about ten > feet or so. I then flipped the magnification to 2X and was surprised to > find that the focus could have been more accurate. > However, looking at 8X enlargements, I could not see any difference in > sharpness from focusing at normal magnification and at 2X > magnification. That doesn't mean there'd not be an observable > difference at greater enlargements, or at a wider f-stop. > Perhaps a better test would have been to focus on a one dimensional > object, but I don't usually photograph such things. Fred Wasti did a > DOF test using a yardstick set an an angle, and with a nail placed in > it. He focused on the nail and was able to determine to some degree > what the DOF was for a given lens/aperture setup. A setup such as that > would, I think, be a good test for focusing accuracy. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
