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Old Jun 19, 2007, 11:07 PM   #11
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Trojansoc wrote:
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Daniel,

I went to the dpreview threads on the subject of backfocusing and, after reading them, I hope that the problem is something other than a backfocusing problem. According to what I have read, the debug option to adjust for backfocus is not open to me since I have already upgraded the firmware to 1.20.

I'm going to do some experiments specifically dealing with the focus question, particularly on AF, because the thought of sending the camera back to Pentax to deal with it is not appealing.

The situation is very serious. Other pict you posted are all out of focus

http://www.stevesforums.com/forums/v...757451#p757451

When I first looked at the soccer pict I did not read it. They all have shown the out of focus problem of most earlier P&S camera using average method in focusing. You have chance of using other AF lens for verification of the issue? How about the Pentax kit lens? Use focus chart or scene where you can verify how much the backfocusing is?

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Old Jun 20, 2007, 3:49 AM   #12
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I would not start jumping to conclusions as yet without checking everything out. Usually if there is a back-focus issue it is not as major as we are seeing here. Back-focus is usually just behind the subject, for example if there is one player chasing another then the back player is sharper than the front. This still shouts to me of the camera selecting something in the background rather than what you were expecting. Also unless I'm mistaken the bird shots are not taken with the K10D as they look very P&S or the birds were too far away and they have been very heavily cropped.

Take so shots of closer static objects and wide apertures lets say f5.6 at 300mm and confirm if it is sharp or not. If it is not looking good then there are more specific back-focus tests you can do.

Just a thought, with the shots you took and didn't post (probably as the action was not as good as here) are all of them out of focus or are there some sharp?

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Old Jun 20, 2007, 7:07 AM   #13
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Good suggestion, Mark. I went back and checked. There were some which had no action that were reasonably sharp, particularly on closer subjects. An example is posted below...taken at 148mm, f5.6, 1/2000, ISO 800.

The bird pictures reflect very heavy cropping and the bird in flight pic was posted for help with identification recognizing its focus flaws.
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Old Jun 20, 2007, 7:31 AM   #14
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Looking at that everything seems OK. The further away a subject is the less sharp is is going to be as you are getting close to the infinity focus of the lens. For example if you have a 200mm lens and you are trying to get good sharp focus then the maximum I would expect would be about 25m. The problem arises the more your camera crops and image as you have to have your subject further away for it to fill the frame. This is why it is easier with my 5D to get very sharply focused shots with my 120-300mm f2.8 at 300mm then with the 30D at 300mm as the same subject is a lot closer when filling the frame so the lens can really go about its business as it is more likely to be in the optimum range of subject to camera. Where possible with soccer shoot portrait and get as much of the frame used while still capturing the action around the player (don't forget the ball :blah

Hope that helps, but as I said earlier do check things out on single shot focus with a stationary object.
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Old Jun 20, 2007, 9:47 AM   #15
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Mark1616 wrote:
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Don't forget to give the camera to 'lock' onto the subject by tracking it for a couple of seconds as that will help. I used the Tamron 70-300 on my Konica Minolta 5D before switching to Canon and found that it did a pretty good job and AF was not an issue for field sports.
what mark says here works great!!

he has helped me alot with this problem!

you really have to focus on the subject, (hold the shutter button half way)

then follow your subject, or at least try to judge where the

ball is going and focus ahead of time! it isn't easy, but it is fun trying!

you really want a challenge shoot indoor volley ball in a small gym!! hahahahaha

anyway, keep working on it! you'll get it!! john
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Old Jun 20, 2007, 4:05 PM   #16
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Mark1616 wrote:
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Hope that helps, but as I said earlier do check things out on single shot focus with a stationary object.
I second that. Use tripod and 2 s delay to ensure zero camera shake.

Your Jose3a.jpg shown above is not conclusive as you might backfocus by 3 ft and there was nothing 3 ft at the back showing the focus point.

I stress this BF issue is very very K10D specific. There are hundreds of thread in dpreview Pentax forum on K10D. General rule applicable to other makes may not apply at all. Can anyone (other than K10D) go to debug mode in their menu to adjust + or - focus point?

Daniel , Toronto
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Old Jun 20, 2007, 6:38 PM   #17
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Do you have unprocessed shots of 1 & 2 you can simply resize and post without any cropping or other adjustments?

That might help us figure out what else might be going on.
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Old Jun 20, 2007, 7:13 PM   #18
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Old Jun 20, 2007, 7:14 PM   #19
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Old Jun 20, 2007, 7:22 PM   #20
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After experimenting with both the Tamron and two other autofocus lenses at tennis practice this morning, I'm convinced the problem is not in the lens or the camera, but in the photographer. I had a return visit from the powered parachute that went over the courts a few days ago and got this with a 400mm Phoenix AF.
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