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06-15-2010, 08:09 PM   #1
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Problem with manual focus

I bought a K200D about a year ago, my first DSLR, so I am sort of new to this. I quickly picked up a used 18-250mm Pentax lens from B&H and it has worked amazingly for the last few months. Recently though, the manual focus doesn't work. By doesn't work, I mean the auto focus still auto-focuses when in manual mode, and I cant turn the focusing ring, it is stuck. I don't want to try too hard because I don't want to break it. This is frustrating when trying to frame a shot and it keeps auto-focusing away from what I want in focus. I tried putting on my 18-55mm lens and the manual focus worked. Any ideas as to the problem? Broken lens? Did I unknowingly apply some setting that prevents manual focus? I have no idea what is going on. Thank you in advance for any help.

06-15-2010, 08:44 PM   #2
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Is there a MF/AF switch on the lens. Maybe it is loose or tight. I had a Sigma zoom with the quasi-macro mode that had a really finicky macro switch.
06-15-2010, 08:51 PM   #3
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No, only a lock switch for the zoom which falls out all the time. The lock has no effect on the focusing ring as far as I know.
06-15-2010, 10:01 PM   #4
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Maybe the AF "hole/button" on the lens is broken since your MF anf AF work on another lens. But then again the AF mechanizim on the camera should retrack when switched to MF and that is very odd that the lens would still AF when the AF button is retracked. Take the lens off and look at the actual AF button on the camera mount while switching between AF and MF. If the button moves in and out then you know its your lens, if it does not move then its your camera.

06-16-2010, 02:10 AM   #5
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I have used the Pentax 18-250 on a K200D ... and on the 18-250 there is no AF/MF switch ...

to MF you need to switch to MF on the body ... and then use the focus ring on the 18-250 ...

that said, the focus ring on 18-250 is extremely stiff with irregular movement ... and not really best suited for MF ... it even made a raspy scratchy sound while turning it ... maybe this is what you assume to be stuck? The sound and the friction had freaked me out a bit as well ... and eventually I stopped trying MF with this lens ...

without putting the body on MF, you should probably not try MF ... as it might damage something ... since the 18-250 does not have a 'Quick Shift' type feature ...
06-16-2010, 10:09 AM   #6
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QuoteOriginally posted by noabsolutes Quote
I bought a K200D about a year ago, my first DSLR, so I am sort of new to this. I quickly picked up a used 18-250mm Pentax lens from B&H and it has worked amazingly for the last few months. Recently though, the manual focus doesn't work. By doesn't work, I mean the auto focus still auto-focuses when in manual mode, and I cant turn the focusing ring, it is stuck.
Are you saying autofocuses even when the switch on the front of the camera is set to MF? Not being able to turn the focus ring while in AF mode would be normal for that lens - unlike the 18-55, it lacks the quick shift function. So it sounds like the lens believes the camera is set to AF. Probably some sort of mechanical glitch.
06-16-2010, 04:26 PM   #7
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that is exactly what happens. I took the advice and took out the lens and flicked the AF/MF switch on the body a few times, and I saw no movement on the camera body. I looked in my booklet at a diagram and found what I suspected was related to the switch, and it said it was the AF Coupler (seen below). I am guessing that is supposed to move but I saw no motion when I flicked the switch. I experimented with the other lens again, and I was wrong, it does the same thing. So it looks like my camera is stuck in auto focus mode. Any idea what could have caused this? Any way to fix it?
06-16-2010, 05:53 PM   #8
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AFAIK, the AF/MF switch has two functions: 1) A mechanical disconnect and 2) An electrical signal to the camera not to use AF.

You can check the mechanical function two ways: 1) Obviously, remove the lens and then switch between AF and MF or 2) Press the lens release button. Either of these should "pull" or retract the AF coupler back into the lens mount. You can also just push on the coupler to verify it's not physically stuck in the "out" position.

If the lens release button retracts the coupler and the switch doesn't, you might be able to use an electrical contact cleaner (spray type) and see if that fixes the problem.

Good luck.

06-16-2010, 06:34 PM   #9
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I tried pushing it in but it just pops right out. Neither the switch, nor the shutter release do anything to it. I think I found a work around though. If I pull the shutter release preview, it doesn't try to re-focus and I can just save the photo. Should work for now. Is there anywhere I can send it to get it fixed? I don't have a warranty.
06-17-2010, 12:10 AM   #10
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You can also set the focus mode to AF-S. This will focus only once when the shutter release is pressed 1/2 way then you can re-compose and shoot. Or if this is available in the 200D (it is on the Kx) you can set the AF/AE-L button to do the focusing and at the same time it disconnects the half press shutter release button as the focusing button. But as for where to send it, sorry I have not a clue.
06-17-2010, 11:12 AM   #11
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QuoteOriginally posted by noabsolutes Quote
I tried pushing it in but it just pops right out. Neither the switch, nor the shutter release do anything to it. ...
You need to check the lens release button instead of the shutter release. If neither the lens release nor the AF/MF switch works some physical linkage must be broken. Unfortunately it can not be easily fixed because that would at least involve removing the lens mount.
06-17-2010, 11:25 AM   #12
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Just an aside here in response to the lens mount theme of the last post. I dropped my K20D with my 300DA* on it last weekend. The lens mount broke right off with the lens. I separated the mount from the lens, screwed it back in..and it is as if nothing ever happened. All working perfectly including AF. Pentax makes some sturdy stuff.

Jack
06-17-2010, 11:41 AM   #13
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noabsolutes,

Check and see if your body is still under warranty. The AF/MF switch should be working as people have already described. If it is under warranty, contact Pentax ASAP.
06-18-2010, 05:07 AM   #14
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I just checked the Pentax website and realized that there's a 1 year limited warranty so I'll call them as soon as possible to see if I can get it fixed. I bought it in October so I still have a few months. Bad timing though, because out here in ND, the flax and canola fields are about to bloom! I may have to wait a tad longer before sending it in. Thanks for all the help.
06-18-2010, 06:27 AM   #15
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In the meantime, you can always use the lens unlock button for a quick focus adjust... Just make sure you don't unmount the lens!
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