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12-27-2013, 05:02 PM   #1
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Mystery of auto focus

Camera is driving me nuts, focusing where it wants,rather than where I want. I mean I could just turn off autofocus, but I would like to learn how to control it. Suggestions?
I see a button marked " af" but the manual just says "focuses on target before metering" ... Is this an important button?

Camera is the K 10d


12-27-2013, 05:20 PM   #2
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Re buttons: You have the option to use the shutter button for auto-focus (which I assume you are using) or the AF button on the back. Never had a K10d but that is true of newer cameras. Check the menus, you should see the option. But it does nothing different, just a preference for which button you want. I prefer using the AF button so that I can focus and then take multiple shots without focusing again but to each his own.

Re focusing: the camera will focus where it detects something contrasty. Until they invent a direct mental link to the camera how do you expect it to know what you want it to focus on? You have several AF 'modes' including 'auto' and 'spot'. Auto will select a point out of those available (up to 11 on the K10d I think) that is in focus and use that to focus on, spot will use only the center point to focus on. Many people who want to have more control over what the camera focuses on use 'spot' and the center point to focus and then re-compose.

May I politely suggest you read through the manual and find an explanation of the various focusing and metering modes, I think the manual explains them better than I can.
12-27-2013, 05:48 PM   #3
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QuoteOriginally posted by jatrax Quote
May I politely suggest you read through the manual and find an explanation of the various focusing and metering modes, I think the manual explains them better than I can.
The manual is a good thing.

I have my K10D in front of me and your options in terms of AF focus points are:
  • AUTO (camera chooses the AF point)
  • SEL (you choose which focus point to use)
  • Center (camera uses the center AF point only)
To trigger AF you can half-press the shutter --or-- push the AF button on the back of the camera. Next to the lens mount is a switch that allows you determine AF mode:
  • AF-S (single, shutter will not fire unless focus is attained)
  • AF-C (continuous AF attempted, shutter will fire if pressed regardless of whether focus has been attained)
  • Off (AF decoupled)
There are other options available through the set-up menus, but they are all variations on the above.

FWIW, I have found AF-C to be almost useless, though there might be some utility if used with continuous drive mode (aka "spray and pray"). I have also found the AUTO setting to be fairly disappointing. The camera usually defaults to the first element in the field that attains focus for any of the eleven points.


Last edited by stevebrot; 12-27-2013 at 06:56 PM.
12-27-2013, 11:56 PM   #4
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I use centre point exclusively on my K10D. The ring surrounding the (OK) button is used on the K10D to set the AF area selection. Mine is on the rightmost setting, and stays there. I have never -- not even to try it -- used the SEL setting. I have used the green all points setting once or thrice when it was appropriate to the subject and my mood and whether or not I had exceeded my ethanol consumption levels.

12-28-2013, 12:51 AM   #5
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Also note that the size of the AF area is not the size of the red focus point indicator that shows in the viewfinder. If you select 'center focus' with the AF mode switching dial on the rear of the K10D (see page 18 of the manual), the AF area that the camera uses for focusing is just slightly smaller than the area covered by spot metering frame (the round brackets that you see in the view finder; page 26 of the manual); so it can find focus on anything in that AF area.

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