On Feb 25, 2011, at 6:42 AM, Boris Liberman wrote: > On 2/25/2011 1:36 PM, Krisjanis Linkevics wrote: >> What is Paul's system? :) >> I haven't adjusted any of my lenses ever but maybe I should so if there is a >> "better" way I want to know! >> >> kris > > I am certain Paul will give you a full answer. Here is mine, kind of second > hand. Paul has made a target which I think he can share. You put it on the > floor, you shoot it with your camera angled approximately 45 deg to the floor > and once you shoot you correct the AF with in-camera correction module. By > doing so you "dial in" or effectively produce an individual correction for > each of your lenses, provided you don't have too many. In case of fast or > "cranky" lenses, such as FA 50/1.4 or zoom lenses such as Sigma 24-60/2.8 > (Sigmas generally being known for AF imprecision) it can be a difference > between lost and made shot. > > Now, since they are offering prices to good fathers, I also dialed in > specifically Galia's lenses for K-7. FA 50/1.4 needed minor correction, DA 21 > and FA 100/3.5 did not. >
It's not really my system. It's pretty much the standard for adjusting autofocus, and Boris has it right. There are alternatives that are somewhat easier to use but more difficult to construct, such as a method where the target is a slope that rises at 45 degrees and the camera is level. The target, whether on the floor or angled up from the floor has a series of evenly spaced line and a central target line. I made my target line slightly bolder than the rest and placed a red dot at its center. After shooting in single center spot autofocus mode, with the center line as the target, you simply observe the results and determine if the center line is indeed the sharpest. If not, you can see if the camera is back-focusing or front-focusing by determining which line is sharpest. The important part is that you shoot of a tripod when adjusting and check the focus at wide open apertures. I also check my results on the computer screen rather than trying to decipher a tiny image on the camera viewing screen. Paul > Boris > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
