Basic Help Needed

Apologies first of all but I have to ask a very dumb question.

I have a K10D with a Std SMC DA 50-200mm lens. On the lens blurb it states how easy it is to change between auto and manual by turning the focusing ring. So I have the front front setting as AF.C, look through the view finder then decide that I need to alter the focus slightly. I press the shutter release slowly and the auto focus takes over again taking it out of my manual focus setting. I must be missing something very basic here!

Bob.

Hi Bob and welcome to the forum

Yes you are missing something. The "quick shift" focus system works in AF-S mode.... auto focus single. The camera locks on to a focus point and stops hunting. As long as you keep the shutter half pressed you can manually fine tune the focus if you wish to...the camera wont try to focus again.

But you are using AF-C mode. Continous AF. The camera will lock on a focus point but if the subject moves or you move the camera the focus will try to refocus continously. This mode is for capturing a moving target. No point trying to fine tune this manually the camera will just take over again.

It is also possible to stop the K10D from initiating autofocus when you half-press the shutter.

When you want the camera to focus, you press the "AF" button on the back with your thumb.

I find this useful because:
1) You can choose centre focus, point at the eyes (for a portrait) and press the AF. Then recompose.
2) For fast moving subject you can prefocus with the AF button on a point, recompose, then jab the shutter when the subject gets to that pre-focussed point (ie. there is zero delay on the shutter)
3) It's helpful in very low light situations, or when taking shots of low-contrast items.
4) When shooting with extremely shallow depths of field you have confidence and control where the focus is.

It takes a little getting used to - but for me it is instinctive and I don't even think about it
(The setting is available in the Custom menu - it's the "AF by Press Halfway" setting )

Incidentally, all the Pentax DSLRs have this feature (The *ist-DS uses the "OK" button to focus).

Hope that helps!!
Matt

Just to say thank you for your very informative replies which have both helped me to understand how to use the manual focus. I could well be back with other questions!

Bob..