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03-10-2011, 03:53 PM - 1 Like   #1
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K-5 1.03 versus K20D AF tests

OK folks, here's today's tests between K20D and K-5 V1.03. I tested both cameras both my FA50/1.4 and Sigma 30.1,4. Aperture for all tests was F/1.4. I first tested in daylight, around EV9 and made sure the AF for both lens was properly calibrated on Both cameras. Interesting to note that I needed to recalibrated both lenses on the K-5 following the V1.03 update. I also tested in brightish tungsten ( around EV6.5)

The three lower light tests were done in a dim room with natural light, with a combination of tungsten light and the computer monitor, and with a combination of tungsten light and the light from the little portable TV on in the background. Hopefully covering a range of common scenarios. Everything was exported from RAW with absolutely no PP whatsoever.

The last test had each lens and camera focussing on the Phones 1 jack plug of my Studio monitor controller. The K20D/Fa50 nails it at EV0.5, but the K20D/Sigma30 back focusses. K-5 FF's with each lens.

Some may remember I posted a test between the K-5's Contrast live view AF and the regular phase AF by shooting a car license plate ( FW1.02). I repeated that tonight with the K-5 FW1.03. unfortunately no better. I'll post the pics later. Hope these tests help .

note: All subject distances were 30"

The shots shown are CROPS to show the pertinent parts of the frame to fit an 800pixel wide pic to upload to this and other forums. The centre focus point of the camera was aimed at the black centre focussing line of the chart in each case and on the Phones Jack 1 in the last test


First the Pentax FA50/1.4 lens wide open at 1.4



















Second the Sigma 30mm/1.4 lens wide open at 1.4












With both lenses at EV1.5 in the room with tungsten/computer monitor light the K20D nails it and the K-5 severaly front focusses. The Sigma on the K-5 slightly Front focusses in natural light at EV1.5


Last edited by Smeggypants; 03-11-2011 at 05:54 PM. Reason: Added more explanation of tests
03-10-2011, 04:00 PM   #2
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Tripod?
03-10-2011, 04:01 PM   #3
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QuoteOriginally posted by sewebster Quote
Tripod?
yes they were on a tripod and heavily cropped.
03-10-2011, 04:02 PM   #4
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i send this with my testreport to pentax,ok??

03-10-2011, 04:03 PM   #5
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Well that's disappointing. Was there any improvement with FW1.03?
03-10-2011, 04:05 PM   #6
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QuoteOriginally posted by Zugzwang Quote
Well that's disappointing. Was there any improvement with FW1.03?
I originally thought there was some improvement, but I really don't think much improvement has been gained on my K-5. especially when I went out and tried the license plate test earlier. must get on and post those....
03-10-2011, 04:06 PM   #7
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Yes,absolut.
In my rooms i can focus very clear with my da*300,90% better with my 50-135 but my 16-45 don愒 like this light.
but,i think a couple of cameras should go to adjust.
03-10-2011, 04:08 PM   #8
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I'm not an expert on this, and don't know what to think really, but the distance of FF seems small, so would a lens adjustment cover it?

Maybe you need to try a different K5? I finally had to give up on that old girl back in school, and by golly, the next one worked out perfectly! Some good memories there, but I won't elaborate, other than to say it was worth the time to give a new body a try.
Best Regards!

03-10-2011, 04:12 PM   #9
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QuoteOriginally posted by Rupert Quote
I'm not an expert on this, and don't know what to think really, but the distance of FF seems small, so would a lens adjustment cover it?

Maybe you need to try a different K5? I finally had to give up on that old girl back in school, and by golly, the next one worked out perfectly! Some good memories there, but I won't elaborate, other than to say it was worth the time to give a new body a try.
Best Regards!
Yup this is my plan. I'm going to contact my dealer again.

If anyone wants to repeat similar tests please feel free. I'd certainly like to see a better performing K-5
03-10-2011, 04:14 PM   #10
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You either have the worst k-5 unit from the entire production or the best k20D from the earlier batch of production.
03-10-2011, 04:16 PM   #11
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These tests mean very little considering you don't have the charts anywhere near parallel to the sensor plane and some are not centered. Failed to convince me.
03-10-2011, 04:22 PM   #12
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QuoteOriginally posted by bogiesbad Quote
These tests mean very little considering you don't have the charts anywhere near parallel to the sensor plane and some are not centered. Fail.
^^^^ FAIL.

1] They are not supposed to be parallel to the sensor plane.

2] Focussing was done on the center of the thick line. The pics were then cropped to show the pertinent parts of the frame.

Here ya go bogiesbad some info regarding focus test charting ... I hope that helps



http://focustestchart.com/chart.htmlt

oh and 3] conditions were identical for each camera and lens
03-10-2011, 04:38 PM   #13
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I have seen vastly enough positive reports to convince me that you have a bad unit...
03-10-2011, 04:42 PM   #14
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Hi Smeggypants
I just want to thank-you for sticking to it and following through with the tests!
Your results only reminds me to take the initiative and do the same when I get my unit.

Based on what I've read to date, it seems many people aren't really bothered by this alone. However, Since I'll be buying into a K-5 specifically for low light shooting, I fear this issue may force me to wait-it-out until its fixed.
03-10-2011, 04:43 PM   #15
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It boggles my mind that your K20D focuses well using the FA50/1.4 in both natural and tungsten light. When I used that combination, I always got a PRONOUNCED shift toward FF in tungsten, regardless of light levels. To compensate, I'd dial up a -9 in focus calibration in tungsten light, and zero outdoors.

So that's weird.
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