I bought a K5 a few months ago. I soon realised that it was front focusing a lot of the time. I did some tests and realised that the maximum manual adjustment was not enough to correct this. I did notice the effect was more noticeable in some lighting conditions, but never thought this was the "low light" problem reported by others. The shop tested the camera with a Pentax-DA 35mm f2.4 AL (result attached f2.4, 1/1250 and ISO 800... hardly low light!). The camera was sent to Pentax UK repair centre, and was returned saying camera was in specification. The shop tested it again and sent it back. Finally, after discussions with Pentax Europe, the camera has been returned to the shop again with no adjustments made. This time they tested with a different lens and claim it is focussing acceptably, and that maybe their 35mm lens was out all along. That also means that every one of my Pentax-A lenses are out too. (Oh, and Pentax Europe claimed that my Pentax-A lenses are too old to use with the camera and I should focus by eye instead. So despite the manual telling us that the focus assist light works with Pentax-A lenses, someone in Pentax Europe feels otherwise!)
I suspect the problem is, as others have reported, that the K5's focus system is extremely sensitive to different light sources. If I accept the K5 back again, I am therefore accepting that in anything other than bright daylight I will never be able to use large aperture prime lenses with the K5... something which is unacceptable to me.
Does this ring bells with other K5 users? What about the K5II? Does it focus more consistently? Or should I simply jump ship to Nikon?
F.