Originally posted by naldopr I have this lens but don't know how to use it on my k3 can you show me how? I m new to this
I've found that two other settings are useful for manual operation. One is the well-known catch-in-focus:
Catch-in-Focus Tutorial - Articles and Tips | PentaxForums.com
To summarize, when properly set up, you start with the lens slightly out-of-focus, press and hold the shutter release, and then turn the focus ring to focus. When catch-in-focus is set, the camera's shutter fires when the focus-detect system decides that focus at the center focus point has been achieved. This eliminates having to eyeball the focus setting, but relies instead on the auto-focus optics.
The second setting is to use catch-in-focus with continuous burst mode on. If you turn the focus ring slowly, you'll find that there is actually a narrow range of focus within which the camera will fire off shots, where the focus system thinks the subject is in focus, due to optical and electronic tolerances. With burst mode on, the camera will fire constantly when in this range, so the more slowly you turn the focus ring, the longer it will take to go through that range, and the more shots will be taken. Especially with hand-held shots, the quality of these bursts varies quite a bit. Some of this variation is due to the interaction between hand shake and vibration reduction, so sharpness varies on a shot-to-shot basis. But you also find that the focus varies progressively over slightly different features of the subject (e.g., from tip of nose to eyelashes, or from tip of a flower to its base). There's an element of a shotgun approach to all this, but some shots within the burst do come out better than others, and those cherry-picked are usually better than my single-shot attempts.
I don't have a K-3, but I suspect, like for other cameras, that you can only use the center focus point for this purpose.