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01-31-2009, 11:13 AM   #1
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Please help me fix my K10D's focus problem

Hi everyone,

I'm about at the end of my proverbial Pentax rope here- sick of dealing with focus issues on my K10D and preparing to either get it all fixed myself, or sell off all my gear and find a new hoppy.

I always suspected an issue with my camera's focusing, but for most of my shots (wide vistas and landscapes, with tiny apertures and gigantic FOVs), it hasn't been an issue. Lately, however, I decided that I want to put my full energy into macro work, but this problem is keeping me from producing results worth the effort.

I've run focus tests with multiple lenses and all appear to have problems of some sort, whether it's decentering, back-focus, or something else, I don't know enough about Photography to tell. What I do know is that all of my lenses aren't duds, and it must be something wrong with the camera.

Can anyone help me diagnose what the problem is with this thing- and please explain to me how I can fix it myself? Or at least ATTEMPT to fix it myself?

These are two recent test shots, the actual test paper shot is done with a DA* 16-50mm, the shot of the pole with my new (old) M 28mm 3.5. Both seem to exhibit a similar issue... the stupid camera isn't focusing where it SAYS it's focusing!

Any ideas? (Please keep in mind- anything that requires connecting the camera to the PC with the USB cord is an impossibility- my camera shipped to me with that port completely damaged, and therefore, totally worthless...)

Thanks for your help!

-Tim



My focal point was the top of the stick- yet the focus appears to get better as you move downward from the top. The stick slanted backward, so the further down it goes, the further away from me it was. Is this back focusing or front focusing?



While the right side of the test appears fine- the left is totally off... what would cause this? I know it's my CAMERA and not the lens, because I tested the Sigma 17-70mm I had at that time in the same way, and it exhibited the same problem.

01-31-2009, 12:01 PM   #2
Damn Brit
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The only thing you can do is send it in to Pentax for adjustment. Also send in a Pentax lens with it (if one is worse than others send that).
01-31-2009, 12:41 PM   #3
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I was really hoping for a different answer, but thank you Gary!
01-31-2009, 12:46 PM   #4
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Before I recently sold my K10, I sent it in (less lenses-silly me) for exactly the same problem just before the warranty ran out. It was back in a week, AF was right on the money.

Don't ask why I waited so long - I have no clue (but that brings up other issues...)

01-31-2009, 12:49 PM   #5
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QuoteOriginally posted by Hannican Quote
I was really hoping for a different answer, but thank you Gary!
You want a different answer, I'll give you a different answer. Live with it and learn to allow for the misfocusing. Of course you'll get fed up with that and by then your warranty will be out.
01-31-2009, 12:58 PM   #6
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Looks like the plain of the sensor is not perpedicular to the lens plain. Could be either the sensor (most likely) or the lens mount on the body. If it is the sensor, you could try pointing the camera lens straight down and running the sensor clean routine to see if you can jog it back into alignment. However, I agree with the posts above that the best option is to send it back in for warranty work.
01-31-2009, 01:19 PM   #7
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I would definitely send it in IF it were still under warranty, but I'm already far beyond that period, so it looks like I'm just screwed at this point.

I'll try Mithrandir's tip and see if that helps- you never know I guess =)

Thanks again everyone.
01-31-2009, 01:49 PM   #8
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I wouldn't be worrying about focus in the first picture - that's *far* too busy of a scene to be sure the AF sensor was locking on to what you thought it was. Although it displays as just a small square, it's actually a *MUCH* larger rectangle, and might just as likely have been giving you the confirmation on the background as the post. BTW, I'm also assuming you are aware that just because the small square lights up that doesn't mean focus is confirmed - that is just telling you where it is *trying* to focus. You have to wait for the hexagon at the bottom of the screen to light in order to have focus confirmed. But in any case, like I said, in a scene that busy, it's kind of irrelevant - there is *no way* to know what the focus confirmation indictor was actually locking on to.

But the difference between center versus the left and right sides of the images does seem an issue. I wouldn't leap to conclusions based on one test, but I'd be running some more tests with multiple lenses. At first glance, it could be a lens defect on the 16-50. The right side seems to be showing focus exactly as it should - the zone of acceptable sharpness extending both in front of and behind the zero line. But of course, the center and left side show something different. Be sure the paper is totally flat, and that you are shooting totally square to it - but really, the problem looks worse than what could be explainend by that.


Last edited by Marc Sabatella; 02-01-2009 at 10:45 AM.
02-01-2009, 08:51 AM   #9
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I don't have a k10D and I am not totally familiar with it's focusing issues, but the first image, I think is within the realm of manual focussing difficulties, again because of the amount of content in it, it could be a difficult scene to get focus spot on the top of the pole. I would run some more tests. That was manual focus, correct? Getting manual focus spot on, where you want it is difficult and you can't trust the hexagon indicator if you want a precise point of focus.

The second image, it looks like it is rotated about half a degree anti-clockwise, and if you look at the outer edges of the test pattern, it looks like it is skewed (i.e. you are shooting from an angle off normal to the test pattern. Depending on the focal length, this could explain some of the issues.

What I would try, is using that same pattern and if you have one, a tripod. Try to get the tripod as square/perpendicular as you can and adjust the paper/tripod until it looks like both sides of the test pattern are sharp and focussed. Then post that image. The resulting image will reflect any skew distortion in your sensor plane.

Out of curiosity, how was the usb connector damaged? Impact damage may cause sensor alignment issues.

Hope that helps?
-southy
02-01-2009, 02:23 PM   #10
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Send it in or get a k20d. The k20d will fix most all lens problems and is quite inexpensive at Prodigital 2000.
02-01-2009, 03:08 PM   #11
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I agree with Marc that the pictures you posted may not necessarily indicate that your camera has a problem with focusing.

The first picture - the algorithm works by maximising contrast on an area - which may have included the leaves in the background.

In the second picture, it seems your camera may not be perfectly aligned with the chart.

I had a similar worry a few weeks ago (see my post then). After extensive tests, my conclusion was the camera was operating correctly, and I was at fault everytime a picture was misfocused.

It wasn't that great on my ego, but at least I didn't have to send the camera to Pentax.

If you really want to focus accurately, buy a split prism viewfinder. I did!
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