As I wrote some days ago the german photo magazine "Colorfoto" researched the possible reasons for AF problems of DSLRs. Here is a short listing:

1.) misadjustment of the AF sensor

2.) IR- and antialiasfilter in front of the chip incfluencing the path of rays (Remember that the AF sensor is at the bottom of the cam. The optical path throgh the lens to the AF sensor differs from the optical path to the chip.)

3.) Pixels are smaller than film grain, so that the tolerance of a DSLR AF is smaller than the one of a SLR AF. In case of old lenses (heavy used or cheap ones) you might get problems as the drive control isn't that accurate. Focus point might vary from shot to shot.

4.) The focus point is measured with a total open aperture. Some lenses show the effect, that the focus points varies in dependence of the effective aperture. In combination with the small tolerance of DSLR AF systems you might get AF problems.

5.) The concavity of the field of view might lead to AF problems, especially if you use wide angle lenses.

6.) Drive control of the lens might stop to fast or to slow. This is a question of adjustment.

7.) Misalignment of lenses

As you can see, a DSLR AF isn't that simple and if you have AF problems it isn't that simple for a laities to diagnose the deciding reason(s). So before you can blame the KM engineers or the KM management for those problems, let's check your cam and the problematical lens.

Here is the link to the german article:

http://www.colorfoto.de/sixcms/media.php/258/0904Autofokus_cofo.pdf


Just my 2 cents

Dat Ei
--
'Charter Member of the Konica Minolta 7D Adoption Society'