Improved AF Accuracy of the K20D (Under White Lights Only)

An experienced Pentax DSLR user, who has a bundle of Pentax AF/digital lenses and various Pentax DSLR bodies including the K100D, K10D and the new K20D, has tested and compared (side by side) the AF accuracy between his K10D and K20D with different higher grade Pentax fine lenses of his putting on both bodies:-

http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=27049158

First of all, here is his detailed comparison tests (two sets - will explain more below) regarding the AF accuracy differences with the DA 21 Limited lens on K10D against the K20D, pair of comparison test shots are posted:-

http://forums.dpreview.com/forums/read.asp?forum=1036&message=27066095

Do note that since the DA 21 was found to have strange focusing behaviour on the K10D that the focusing accuracy actually depends on the Av number selected (as well as if the lens is turned from the infinity or closest), which I have reported here before, the user also carried out a second batch of the test in the above to compare the focus accuracy of the K10D against the K20D under the procedure which he believed his K10D should work best.

Well, as it is mentioned in the user's opening post and can be seen from the above detailed tests and measurements, there are significant focusing errors with the K10D whereas with the K20D could do very well with the same DA 21 (and other various Pentax AF lenses he has as well, as told - so far he has not posted all the test photos with all different lenses in the thread, though).

Indeed, I was a bit susceptible on his report when I first read his opening post just because usually people would have some kind of honey moon period effect when they've received their new toys and usually think that the new toys are better (maybe just because they've got excited or actually time will tell for many things, when they use their "new" gear longer). However, since there is some solid measurbation evidence shown above, I think I should believe.

In fact, I am really glad and pleased that Pentax have improved their design finally (as it seems to be from judging from the above) after years of the same persistent AF problem for inaccuracy, at last. I do think that "late is just better than none"!

Well, I do believe that it is always a good thing to let Pentax and the public know about those annoying gear problems as wide as possible so that Pentax should listen and potential buyers/users should be fully aware of such problems as well, before they are sold. Furthermore, for letting more people to know about the problems, more pressure would be made to Pentax so that they are forced to improve to a certain extent, instead of letting the problems drag on for long or even forever! That's is in fact my clear objective in setting up and updating my this blog.

Now, have all the AF accuracy problems (just say for shooting static objects only) been resolved totally? So, what are some of the well-known problems? Just read back my early Blog article about the "AF Accuracy's Dependency on Lenses and Yellow Light", then you will know more about these.

On the other hand, here comes the bad thing as reported also by the above Pentax user who carried out also the test to verify if AF accuracy has been improved under the yellow lights, i.e., tungsten light source or any artificial light source with low colour temperature. Unfortunately, he found that obvious Front Focusing *still* occured, as always for ALL Pentax DSLRs:-

http://forums.dpreview.com/forums/read.asp?forum=1036&message=27066212

This is yet a disappointment, although I would not be of big surprise. In contrast, I have been surprised this time for what it has been proved that one of the most annoying "Pentax's" problems has actually been removed, with the K20D.

Since I shoot a lot under tungsten lightings which are often dimmer conditions, I had found that such AF system problems to be a big annoyance. This is in fact one of the main reasons that I was forced to get a Canon 5D kit in June last year. Later on, I got also the Canon 50/1.8 fast prime which I have never seen the Yellow Light Symptom of the Pentax DSLRs (which I was the very first person on the Net to conduct a quick experiment to verify this problem), even at fully wide opened and under very dim conditions and even with low contrast objects. More importantly, the focusing was still fast and decisive with the 5D at lower light conditions, unlike all other Pentax DSLRs that would hunt seriously in the same conditions. Moreover, do note that Pentax film AFSLRs like the expensive MZ-S flagship and the entry level model MZ-30 which I have both do not slow down like what the Pentax DSLRs would do under lower light conditions, neither. Nevertheless, the MZ cameras do shift a little bit with slight front focusing under tungsten lightings but the magnitude is not that large as those Pentax DSLRs - that I can tell - just believe it or not!

A few days before, I tried two units of the K20D, I am not overall impressed with the AF responsiveness of the K20D neither. That says the K20D required to think longer than I would expect for the AF motor start to move and it also need longer time to re-confirm the focus and re-adjust the lens as well. This slow responsiveness that I can feel easily is not really a good thing, IMHO.

Last but not least, here are the remaining posted test results (a few pairs of shots only) for the AF accuracy comparison between the K10D and the K20D with a few other different lenses which the above mentioned user has, which proves again the AF accuracy of the K20D has improved whereas the AF accuracy of the K10D is just rather poor:-

http://forums.dpreview.com/forums/read.asp?forum=1036&message=27066277

So, for those old Pentax DSLR users who have being wanted to upgrade just because of the particular deficiencies they don't like and ask me if it worths the upgrade to the K20D by now. My answer would be "Nope" at the current stage, undoubtedly. It is just because I won't spend another (US)$1,400 to cure only one of the long lasting and well known problems which exist mainly in all the previous models of Pentax DSLRs. Unless later on it can be confirmed that more of the old typical Pentax problems for the camera performance and accuracy aspects are cleared (like this time for the AF errors with different lenses), it is just too risky to put the bet *now*, I would say. Note that for $1,400, actually we could already invest into a few good lenses in the basic focal range for another better system, even if we are to start from scratch, like what I did last year (although these glass may not be as good as some of the original Pentax glass! ;-))