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10-31-2009, 11:41 AM   #1
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My new K-x is front focusing, now what?

My K-x is front focusing <see photo>..
The same lens on my K20d focuses normally.

What is this "debug mode" I have heard about?
Has anyone confirmed this can be fixed using debug mode with the new K-x?



10-31-2009, 12:10 PM   #2
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QuoteOriginally posted by skid2964 Quote
My K-x is front focusing <see photo>..
The same lens on my K20d focuses normally.

What is this "debug mode" I have heard about?
Has anyone confirmed this can be fixed using debug mode with the new K-x?
The debug mode was very effective with my K10, but I would first test if your other lenses do also have front focus. If they are also FF-ing then I would return the body now that's still brand new. My K-X is spot on with all my lenses except the DA12-24, but that is lens related, because on my K10 it was also way off.

BTW, did you test with daylight, you should....
10-31-2009, 01:30 PM   #3
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QuoteOriginally posted by tomtor Quote
The debug mode was very effective with my K10, but I would first test if your other lenses do also have front focus. If they are also FF-ing then I would return the body now that's still brand new. My K-X is spot on with all my lenses except the DA12-24, but that is lens related, because on my K10 it was also way off.

BTW, did you test with daylight, you should....
I just tested in daylight, same result, my kit lens is FF also.
Won't they simply do the same thing I would do? adjust in debug mode?
10-31-2009, 01:31 PM   #4
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QuoteOriginally posted by skid2964 Quote
I just tested in daylight, same result, my kit lens is FF also.
Won't they simply do the same thing I would do? adjust in debug mode?
If the FF is consistent, I guess you could try debug menu. Problem is, K-x has 11 AF sensors. That's a lot of work to do to calibrate them all (well - you can try it only with the center one). I'd try to replace the body.

10-31-2009, 01:51 PM   #5
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Or jsut send to Pentax.
10-31-2009, 02:21 PM   #6
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QuoteOriginally posted by skid2964 Quote
My K-x is front focusing <see photo>..
You need to center the test target on this chart - that's the whole point. If you point at the scale on the side, the camera can legitimately choose to focus on one of the numbers closer to you. And that seems to be exactly what it did Repeat the test with the focus target centered like the instructions explain.
10-31-2009, 02:33 PM   #7
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QuoteOriginally posted by Marc Sabatella Quote
You need to center the test target on this chart - that's the whole point. If you point at the scale on the side, the camera can legitimately choose to focus on one of the numbers closer to you. And that seems to be exactly what it did Repeat the test with the focus target centered like the instructions explain.
Ok, I will try that first.

Is this because the focus area is large enough for that to happen? Would the focus area be smaller on my K20d and give better results while incorrectly performing this test?
10-31-2009, 02:53 PM   #8
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Ok, I followed the instructions this time, LOL...
Does this look better? it is hard to tell. I know the "focus here" words seem to be sharp.
But it still looks front focused to me.



10-31-2009, 02:55 PM   #9
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Looks pretty damn good to me.
10-31-2009, 02:56 PM   #10
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LOL i was about to point out that the skid2964 has obviously cropped the image to show the text/scale part better, but Marc was actually right and the test was performed incorrectly.

I believe you've tried with few lenses, just to see what's really happening.

Anyway, if you confirm that your camera has front focus, since it's new and you still have your k20d to shoot with, i'd reccomend to send it to Pentax.
If i recall correctly from one of Pentax service manuals they are correcting position (height) and tilt of the AF sensor. If it is a bit too high or low it should adjust well in debug mode, if it is tilted too much you will get good focus at some distance and bad at others (just a guess).

Update: After seeing your new test the focus seems to be perfectly fine. I have more FF with DA70/2.4 on k200d (around 2 to 6 mm) and it can't be seen in most pictures anyway (still, it's only f/2.4 so the text is in focus along with the 2 and 6mm, just a bit softer) - that is i've never seen it in any other pictures than tests specifically done to show it. Btw, are you taking this at 45 degree angle, because it seems that it is lower than that - it can change the FF/BF reading:
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Last edited by ytterbium; 10-31-2009 at 03:18 PM.
10-31-2009, 02:58 PM   #11
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QuoteOriginally posted by skid2964 Quote
Ok, I followed the instructions this time, LOL...
Does this look better? it is hard to tell. I know the "focus here" words seem to be sharp.
But it still looks front focused to me.
Looks good. Nothing to worry about. Such "front focus" is not field relevant.
10-31-2009, 03:06 PM   #12
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Sigh.

There's nothing wrong with your AF. I wonder how many cameras Pentax (and Nikon, Canon ...) have sent back to them due to this sort of testing.
10-31-2009, 03:07 PM   #13
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Take some real photos in the field and carefully focus with just the center AF point. If you are finding that the camera is front focusing, then you should worry. You'll end up pulling out your hair expecting perfect results with poor technique.
10-31-2009, 03:40 PM   #14
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Thats why Im on this forum, trying to confirm before I make any rash moves. In my rushing the first test,
I neglected to do it properly. Thanks to all for pointing out my error.

So this minor FF is nothing to be concerned with?
It was taken with a FA 50mm at 1.4
Would this be a concern if it were a 1:1 macro lens? (I guess you would manually/visually focus in that situation anyway).
10-31-2009, 03:44 PM   #15
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QuoteOriginally posted by skid2964 Quote
Thats why Im on this forum, trying to confirm before I make any rash moves. In my rushing the first test,
I neglected to do it properly. Thanks to all for pointing out my error.

So this minor FF is nothing to be concerned with?
It was taken with a FA 50mm at 1.4
Would this be a concern if it were a 1:1 macro lens? (I guess you would manually/visually focus in that situation anyway).
Heh, I rarely have the text in focus with my FA 50/1.4. Yours is almost spot on. Be glad
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