Originally posted by creampuff Where are all the photos with the supposed problems?
With all due respect to bjan and Pentaxeros all talk and no photos means nothing.
I haven't encountered the kind of focus errors with my K-5 with my fast lenses and if there were, it could be for a number of reasons, user error being one of them.
The problem is not "supposed" but very real, and it does not just exist in tungsten, but also in candlelight. It appears that it is light with an orange/yellowish hue that fools the AF system.
Here are some self-explanatory images from the tests I ran. I'd encourage every K-5 owner to do this very easy test: no light except one candle, and a contrasty object next to it (in this case the K-x manual because it was at hand). The funny thing is that I've tested my K-x with the DA70 in this same scene and it nails focus almost every time.
In my experience, the K-5 is able to focus much darker objects than the booklet cover in this scene, but only if it activates the AF assist lamp. The problem is, in this scene, the camera doesn't think it needs the AF light to achieve focus, and indeed the AF confirmation comes very quickly. Unfortunately, it misses pretty much every time. I wouldn't be surprised if the problem was solved by manually forcing the AF assist lamp to work, but as far as I know there is no way to do this.
Unlike what Pentaxeros mentioned above, I'm not convinced this can be solved by simply dialing -10 AF microadjustment. I think -7 or -8 generally looks best (but not in focus, as shown by the images focused with LV), further than that it seems to get worse. Oh, and the AF microadjustment seems to mess with AF accuracy in daylight and at longer distances (as I found out this morning with my DA18-55)
All in all,
extremely annoying, and something that Pentax needs to fix
soon.
These were all taken with K-5 and DA70 or DA35 at the largest aperture allowed by each lens: