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11-18-2010, 07:31 PM   #1
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my K-r AF test

Hi guys,
I got my new K-r for 2 weeks, everything is fine but with af under tungsten light.
I have tried "Moire' Interference Patterns" @ Using Moire' Interference Patterns to Test DSLR Auto Focus, af is fine under normal light, but I found some BF/FF situation under tungsten light.

Here are some test images done last night. Handheld with FA31 ltd.

1. the test setup


2.


3.


4.


5.


6. tried with no af adjust again, still bf/ff



did i get a defect K-r?

11-18-2010, 08:27 PM   #2
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btw, I also tried with K-m, which in general did better result than K-r.
But setting K-r with tungsten wb and af adjust -5 looks more precisely.

Wish it can be fixed by new firmware.
11-19-2010, 05:06 AM   #3
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I have the same problem with my Kr (see my post in this forum). I can't trust the AF in tungsten light.
11-19-2010, 07:13 AM   #4
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Isnt BF/FF under one sort of artificial light or another depending on camera, an issue for most cameras? Be it Tungsten or fluorescent.

I also noticed the issue with my K-r under tungsten but it was worse depending on which lens I used.

Also it seems in your test that the Tungsten white balance setting results in better focusing under Tungsten than AWB.

11-19-2010, 09:00 AM   #5
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yes, tungsten wb setting results better. but even K-m AWB works better.

I think the af should be more consistent! especially when shooting under more complicated light sources, like wedding, stage performance...

Last edited by cloud016; 11-19-2010 at 07:36 PM.
11-20-2010, 02:46 PM   #6
elg
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Did anybody try to put color correction filter (tungsten->daylight. The real one, not a digital effect, as the filter correction must 'be seen' by the autofocus sensors) and then see what happens? If focus depends on color temperature, then maybe this could be a workaround?

Cheers,
elg (Erika)
11-21-2010, 12:16 AM   #7
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QuoteOriginally posted by cloud016 Quote
yes, tungsten wb setting results better. but even K-m AWB works better.
Did you notice the menu item where you can choose the strenght of the WB adjustment under tungsten? I see a clear difference between the two options in AWB but don't know if it has an impact on af.
11-21-2010, 06:52 AM   #8
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QuoteOriginally posted by ovim Quote
Did you notice the menu item where you can choose the strenght of the WB adjustment under tungsten? I see a clear difference between the two options in AWB but don't know if it has an impact on af.
I tried. no better for autofocus.

11-21-2010, 01:48 PM   #9
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Last night (after reading this and a few other threads) I did a quick poor-man's test on an empty paper baguette bag with writing down the side at a 45 degree angle. Focused on a period in the middle and with AWB, it was front-focused by 3-4 letters (just under an inch?) and set to tungsten it was front-focused by 1-2 letters. Using the DA* 16-50 lens.

Almost makes me want to get a K-5. :P (But at double the price for the body... not now.)
11-21-2010, 04:46 PM   #10
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af adjust, fixed, its easy enough to turn on/off and to adjust. we'd all love it to be perfect, but at least there is an option to deal with it
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