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09-09-2011, 11:38 PM   #1
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K-r front focussing

Has the front focussing issue on K-r's been addressed yet and is it common on all K-r's or just some?

09-10-2011, 12:10 AM   #2
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I don't think it's an issue with the K-r.

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09-10-2011, 12:22 AM   #3
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it would seem then that I have a faulty K-r.
I have been concerned for some time so I used a ruler and angled the camera at about 30 degrees at about 35cm using an M 50 1.7 lens and focussed on 50cm on the ruler and when I viewed the results the focus was clearly between 65 and 70 and when I focussed on 30 then it was in focus on 50.

I did the same with my old K100D super with the same lens and it was fine.
09-10-2011, 07:34 AM   #4
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The M50/1.7 is a manual lens. Focusing a manual lens doesn't have anything to do with autofocus.

It is possible that the optical path through the mirror is different than the path to the sensor, which would make manual focusing difficult. But that is a separate issue.

09-10-2011, 08:23 AM   #5
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Well the focus confirmation light could be off, even though it is a manual lens.
09-10-2011, 11:53 PM   #6
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Yes it is a manual lens but the focus indicator showed that it was focussed.
I have attached sample photos
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09-11-2011, 12:01 AM   #7
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The focus light indicated that it was in focus when in reality it wasn't
09-11-2011, 12:06 AM   #8
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The AF confirmation system normally gives you a good amount of slack, unfortunately. FF/BF can only be measured with an AF lens.


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09-11-2011, 12:07 AM   #9
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Sample photos are attached
1 K100D focussed at 50mm
2 Kr focussed at 30mm
3 Kr focussed at 50mm
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09-11-2011, 03:14 AM   #10
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As far as I know, there is no such thing as the "K-r FF problem".

You may want to check the problem with an AF lens as well.
If the problem remains, you may want to bring in the camera for warrenty repair.

Bert
09-11-2011, 04:16 AM   #11
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Thanks Bert,

That is my next step.

Although, I first became concerned because of the results with my AF lenses -- I will be taking some test shots with AF.
09-11-2011, 06:58 AM   #12
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QuoteOriginally posted by bymy141 Quote
As far as I know, there is no such thing as the "K-r FF problem".

You may want to check the problem with an AF lens as well.
If the problem remains, you may want to bring in the camera for warrenty repair.

Bert
There is certainly a K-r "front-focus under artificial light" problem that some users including myself are having...
Please search in the K-r section of the forum.

Michel
09-11-2011, 08:45 PM   #13
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I have run the same test with my Sigma 50mm 1.4 DG HSM with the same results, see below.
I guess that this really is a warranty issue with the focussing mechanism.
Thanks for all your comments.
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09-12-2011, 09:54 PM - 1 Like   #14
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Tests with a ruler are meaningless. The camera has no clue which line you want it to focus on. The confirmation light will come on if *any* lone within range of the sensor is in focus.
09-13-2011, 10:47 AM   #15
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Look at focus test charts to see how they are designed. The idea is to have one element in the middle, with high contrast so the AF sensor can see it, large enough to think it's worth focusing on, and with space around it so no other objects attract the AF sensor's attention. The charts have scales but placed off to one side, to give an idea of where the focus point was and put a number on it.

The charts also come with instructions about camera placement and setup.
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