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Old May 10, 2010, 5:39 PM   #1
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This weekend I packed up my camera, a couple lenses and went to Lakelands annual "May fair by the lake" art fest. It was was a nice experience but, I was extremely disappointed with the results of my photography. To start off with, I was using the Pentax 12-24mm. When I would aim, press the shutter halfway to focus, the press fully to shoot, the shutter wouldn't release. This happened in about 90% of my tries but, not all. Even in the shots where I got focus lock and it took, they were still very soft looking. I finally changed to the 55-300. That lens work much better locking focus but, I still had a high rate of soft looking photos (99%) Also metering was way off. on the 12-24 when I pushed the green button it was telling the camera to use 1/8th or 1/10th second for shutter speed @ f:4 when I pushed the green button when I actually need f:10 @1/500th. Other lenses seem to meter OK. Anyone have any suggestions?
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Old May 10, 2010, 8:36 PM   #2
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are u using spot metering? if i have my k20 set to center focus opposed to the 9( 8 or 9?) point focus it will allow me to take pictures regardless whether the camera think its locked on or not. When on the 8 or 9 point auto focus, sometimes even when its fully focused on auto mode, the k20 will still keep hunting with certain lenses and lighting conditions preventing me from pressing shutter.

At first i thought my camera was broken but i think it is just the camera trying to tell me its not ready to take the shot with current conditions.

im not sure if this is related or not but like I said, try it with center focus on if u havent already and see if it still does it.
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Old May 10, 2010, 9:45 PM   #3
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I had front focus problems with the 12-24, especially with the K7. And it wouldn't focus to infinity no matter how far away an object was. I finally shot some focus charts, adjusted the focus for that lens and haven't had any trouble since. Did the lens have a lock before you push the shutter the rest of the way? Until I corrected the front focus problems I sometimes had trouble getting the 12-24 to focus (moving the camera slightly sometimes helped it to lock onto something with enough contrast).

How's your battery? I sometimes have metering problems if my battery is low. But I've never had one lens be consistently way off like that. Might also check the contacts on the lens.

Otherwise, I'm clueless.
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Old May 11, 2010, 5:22 PM   #4
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Quote:
Originally Posted by NMRecording View Post
are u using spot metering? if i have my k20 set to center focus opposed to the 9( 8 or 9?) point focus it will allow me to take pictures regardless whether the camera think its locked on or not. When on the 8 or 9 point auto focus, sometimes even when its fully focused on auto mode, the k20 will still keep hunting with certain lenses and lighting conditions preventing me from pressing shutter.

At first i thought my camera was broken but i think it is just the camera trying to tell me its not ready to take the shot with current conditions.

im not sure if this is related or not but like I said, try it with center focus on if u havent already and see if it still does it.

Yes, I almost exclusively use spot metering and center focus. The funny thing was, even in manual focus mode when I got the camera to fire, it still wasn't a good sharp image. you can see in the photos I posted from the art fair http://forums.steves-digicams.com/pe...-art-fair.html that all my images are on the soft side and these have all had all the sharpening it could stand from CS4.
I'm starting to think I must have some haze or something on my lens, due to the construction of this lens its hard to see the rear glass. I'm going to have to do some more testing and comparison shots to try to figure this out. Thanks for you input though.
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Old May 11, 2010, 5:28 PM   #5
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Originally Posted by mtngal View Post
I had front focus problems with the 12-24, especially with the K7. And it wouldn't focus to infinity no matter how far away an object was. I finally shot some focus charts, adjusted the focus for that lens and haven't had any trouble since. Did the lens have a lock before you push the shutter the rest of the way? Until I corrected the front focus problems I sometimes had trouble getting the 12-24 to focus (moving the camera slightly sometimes helped it to lock onto something with enough contrast).

How's your battery? I sometimes have metering problems if my battery is low. But I've never had one lens be consistently way off like that. Might also check the contacts on the lens.

Otherwise, I'm clueless.
Thanks for your response, Harriet.
Yeah, I tried all the above and the battery was fresh. I can't recall if it locked on focus or not but, I'm thinking it didn't until I put it in manual mode. anyway, I need to do some more testing.
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Old May 12, 2010, 11:33 AM   #6
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I'm not sure the lens is at fault. You mentioned swapping lenses and still getting soft focus 99% of the time as well as bad inaccurate metering. I's start by cleaning up the contacts on both the body and lenses. Perhaps something is preventing the camera from communicating with the lenses properly. Also, take a look at the mirror to make sure it's clean as well. If the mirror has dust in it, it will cause focusing issues. Lastly, put the camera in P mode, set ISO to AUTO and take some shots. Then record the ISO, S and A values, go to manual mode, replicate the settings and the shootings. The images should be identical. If not, something is definitely wrong with the camera.
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Old May 12, 2010, 12:21 PM   #7
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I'm not sure the lens is at fault. You mentioned swapping lenses and still getting soft focus 99% of the time as well as bad inaccurate metering. I's start by cleaning up the contacts on both the body and lenses. Perhaps something is preventing the camera from communicating with the lenses properly. Also, take a look at the mirror to make sure it's clean as well. If the mirror has dust in it, it will cause focusing issues. Lastly, put the camera in P mode, set ISO to AUTO and take some shots. Then record the ISO, S and A values, go to manual mode, replicate the settings and the shootings. The images should be identical. If not, something is definitely wrong with the camera.
Good insight to investigate here.
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