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05-05-2008, 06:13 PM   #1
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K10D auto focus problem?

I've just read on dpreview that the K10D has auto focus problems, and one must calibrate each of his lenses to properly focus by downloading new firmware, and then going through a long list of instructions.

Is it true that each K10D owner has to do this in order to get the camera to focus properly with different lenses? I have never heard of such a thing. If true, can't Pentax make a repair that makes the camera able to auto focus with all lenses? Thanks for your replies. Tom

05-05-2008, 06:25 PM   #2
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Every manufacturer is having Af accuracy problems. For some reason. with DSLR cameras we are seeing either front or back focus, something we never saw with film. Now for sure, some of this is because we can blow things up to humungous virtual dimensions on screen and pick out every flaw in the image.
With the K10, there was a hidden menu available that allowed AF biasing, but it was global, in that the AF system itself was affected. Pentax took this way in later firmware updates. I think after the second update, they had rehidden the menu.
With the K20, you can bias as many as 20 different AF lenses into the camera.
Apparently, no one can make an AF camera that has accurate AF with all lenses.
05-05-2008, 08:36 PM   #3
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Yes I have also founf that after connecting my sigma 17-70 it too had AF problems

Went to take a shot of a piece of white paper to see if any dust is present and its going in out in out etc

Is this fixable with firmware updates

cheers
05-05-2008, 08:56 PM   #4
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To the OP - no this is not true. The vast majority of people have no trouble with their AF. The small percentage that do (about the same percentage as with other cameras - just search their forums for complaints) are the most vocal. Not many people take the trouble to post that their camera is working fine. However, when it doesn't appear to work the way it's expected, one of the first things people do is look on the internet for answers.

There was a hidden service menu (that practically ALL camera manufacturers have) that someone found that would allow the service tech to adjust AF. Later firmware updates closed that hole. The K20D put that into the user menu, as does Canon and Nikon, IIRC. This is merely a convenience, and a recognition that ALL mechanical systems will need adjustment at some point.

As for the other poster saying you're having problems focusing on a blank sheet of paper, you need contrast to fix focus. That's how the system works. There is nothing wrong with your AF.

05-05-2008, 08:57 PM   #5
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QuoteOriginally posted by cupic Quote
Yes I have also founf that after connecting my sigma 17-70 it too had AF problems

Went to take a shot of a piece of white paper to see if any dust is present and its going in out in out etc

Is this fixable with firmware updates

cheers
That isn't a firmware problem.

Shooting white paper with AF will cause problems as you found. Use Manual focus because the AF sensor often cannot find anything on smooth white paper to target.

I actually find that shooting at clear blue sky (with MF) to locate dust works better.

If you are worried about Front Focus FF or Back Focus BF issues, you will need to target a solid object, focus on it, shoot it and then look at the picture on your PC screen (better for detail than the in camera LCD). If your object is sharp, you don't have a problem, if whatever is behind your target is sharp instead of the target, then you have a BF issue and vice versa.

Hope this helps.

Edit Note: Forgot to say, if you think you have a BF or FF issue, I recommend you don't screw with reflashing earlier firmware versions to get that maintenance menu as many have done, some successfully, others not. Take the trouble to send it to Pentax for repair, otherwise you may not only void your warranty, but screw your camera as well.
05-05-2008, 09:11 PM   #6
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QuoteOriginally posted by cupic Quote
Yes I have also founf that after connecting my sigma 17-70 it too had AF problems

Went to take a shot of a piece of white paper to see if any dust is present and its going in out in out etc

Is this fixable with firmware updates

cheers
And none of the other posters referring to your post got the humour! I love it!
05-05-2008, 09:21 PM   #7
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QuoteOriginally posted by Canada_Rockies Quote
And none of the other posters referring to your post got the humour! I love it!
eerrr . . wife says I need a humor implant. In the meantime CR, can you enlighten me as to what was humorous? I am being serious here . . .
05-06-2008, 05:26 AM   #8
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I repeated cupic's test, and not only did the focus hunt forever, when it finally took the shot, the white paper turned out gray! Oh, the horror!

05-06-2008, 05:29 AM   #9
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OK, what was humorous was ANYONE WITH ANY KNOWLEDGE OF AUTOFOCUS TECHNOLOGY would not expect ANY autofocus system to lock on a sheet of white paper. So either cupic was making a joke (like my post above), or s/he needs to get some knowledge of how autofocus works. Hint - it needs contrast to work. White paper=no contrast.

Do I need to explain the "grey" sheet of white paper?
05-06-2008, 05:30 AM   #10
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Since I'm jacked up on coffee now (have a three week old at home now), my K10D had NO problems with the accuracy of autofocus on any of my lenses. It wasn't the fastest (why I switched to a 40D), but it always was spot on.
05-06-2008, 06:35 AM   #11
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QuoteOriginally posted by egordon99 Quote
OK, what was humorous was ANYONE WITH ANY KNOWLEDGE OF AUTOFOCUS TECHNOLOGY would not expect ANY autofocus system to lock on a sheet of white paper. So either cupic was making a joke (like my post above), or s/he needs to get some knowledge of how autofocus works. Hint - it needs contrast to work. White paper=no contrast.

Do I need to explain the "grey" sheet of white paper?

Thanks I think


This post wasnt meant to be a joke so whats there to be mystified about?

I relaised after that the question sounded that i was taken the mickey but as I

just started on my first Dslr Im in fact a newbie so please be kind

cheers

05-06-2008, 08:22 AM   #12
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QuoteOriginally posted by cupic Quote
Thanks I think


This post wasnt meant to be a joke so whats there to be mystified about?

I relaised after that the question sounded that i was taken the mickey but as I

just started on my first Dslr Im in fact a newbie so please be kind

cheers

We are ALWAYS kind. As for sarcastic, that is another story
05-06-2008, 02:37 PM   #13
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Sorry, Cupic! I thought you were trying to be humorous - my bad.

If you want to check focus with a white sheet of paper, you will have to draw a line or spot for the camera to focus on. It works on contrast edges. There are other cameras that use Infra Red focusing or sonar, but the dSLR works on the edges of items.

The white paper will come out gray unless you add exposure compensation. I should start with about 1.5 stops and work my way from there.

Enjoy the forum! We do.
05-06-2008, 03:02 PM   #14
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Original Poster
Thanks, Rob. Your advise is sound. I figure I have as much of a chance of learning how to fly a 747 jetliner as I do learning how to work with the firmware instructions for "solving" this problem. (I do have a BF problem with the 16-45.) I'm just 20 minutes away from the Pentax Service Dept. address on the manual. Don't know if they take walkups, but will give it a try. Thanks again!

Tom

Edit Note: Forgot to say, if you think you have a BF or FF issue, I recommend you don't screw with reflashing earlier firmware versions to get that maintenance menu as many have done, some successfully, others not. Take the trouble to send it to Pentax for repair, otherwise you may not only void your warranty, but screw your camera as well.
05-06-2008, 03:55 PM   #15
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cupic mate,

There's an easier way to check for dust.
Set your aperture (f value) to the highest number possible with your lens (usually about 22 or 32 - or even 40 with the 18-55mm lens at 55mm), and by focusing first on something like a far away tree point the camera up into the blue sky and take the shot.

Knowing that the sky is a clean blue, any dust will come up as specs on the screen corresponding to where the dust spots are on the sensor.

If there's dust there, try blowing them off the sensor before you try anything else - you might be pleasantly surprised with the results...
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