Originally posted by rasebe High everyone. Fairly new to posting much prefer to read than post however I am having a little bit of trouble with AF in low light. Love the camera this is the first proper Digital camera I have owned and its fantastic. Problem is when I attach either my Sigma 24-70- f2.8 or 70-200 f2.8 in very low light i tend to get a lot of focus hunting which sometimes results in OOF pictures. Neither of these lens are SDM, down to price you know! Some 'experts' have suggested K% is poor in low light but when I bought the camera id was rated as probably the best low light camera in its price range. I take a few theatre pics and as such lighting can be a issue. Should I update the camera to K511 or K3 or change the lenses to HSM?
I have used AF SLRs since the mid 1990s, and the K-5 does fine in low light. It does not suck. Try this little trick next time. (I am assuming you are using the shutter release to do your autofocusing as well.)
You are trying to lock focus and it won't, it is hunting some.
1) While still holding the camera like you are taking a shot, tilt the camera 45 to 90deg.
2) Lock focus AND HOLD IT (= keep the shutter release half pressed).
3) Recompose and finish taking the shot.
Sometimes that is all it takes, because AF sensors often times still are more sensative in one orientation than another. Note how the camera manuals often times illustrate how cameras don't like focusing on venetian blinds and the like? They get confused by the contrasts they are seeing in one orientation. Often times all you have to do is just change the orientation of the camera to the scene to get the AF to lock.
Try it, you will be surprised.