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11-11-2013, 01:06 PM   #1
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Kr to K500 - Chromatic aberration issue

Hello,

I've bought a K-500 yesterday to replace my Kr and, although it has many improvements, including a better noise reduction, I can't understand one point : the huge degradation of the chromatic aberration between the kr and the k500. I noticed this major issue by taking the same shot in the same conditions : same lens, a DA 35mm 2.4, same aperture 4.0, same speeds with over and underexposures) in low light (home) and with 6400 ISO, taking the shots with 12M pixels for both cameras (I've tried with 16Mp with the K-500, same result), and with and without CA correction.

After many tests, it is obvious that, on this point, the K-500 is outperfomed by the Kr, something I absolutely did not expect. Indeed the Kr's pictures don't show any CA (few with a lot of zoom) but on K-500's pictures, it can be seen without any zoom directly on the K-500 screen!

Did someone notice the same problem? Does it come from the new sensor and the higher resolution? Would it be a problem with my K-500?

Im' considering to return the K-500 to the shop and continue with my good old Kr... the upgrades between the 2 cameras seem really poinless if the CA is so badly managed in the K-500.

Thank you very much for your help.

11-11-2013, 01:19 PM   #2
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I'm no expert, but I've always heard that CA is a lens issue, not a camera issue. I'm thinking that the K500's improved sensor and higher resolving power (over the K-r) is exposing the lens' deficiencies, and that's what you're seeing. I may be completely off-base, hopefully someone more knowledgeable than me will jump in. I also have the DA35 2.4, and it's a fine lens. I rarely encounter CA using it with my K10D.
11-11-2013, 01:26 PM   #3
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QuoteOriginally posted by paulh Quote
I'm no expert, but I've always heard that CA is a lens issue, not a camera issue. I'm thinking that the K500's improved sensor and higher resolving power (over the K-r) is exposing the lens' deficiencies, and that's what you're seeing. I may be completely off-base, hopefully someone more knowledgeable than me will jump in. I also have the DA35 2.4, and it's a fine lens. I rarely encounter CA using it with my K10D.
QuoteOriginally posted by paulh Quote
s' def
Thanks for your reply. Indeed I've thought the same thing, the K500 sensor showing the lens deficiencies...
But for me, not an expert, it seems really strange that an almost non-existing issue (whithout any CA correction) in the Kr becomes a major issue in the K-500 used in the same conditions (the DA 2.4 35mm is not a so old lens).
If the K500 shows the deficiencies of the lenses, I would consider anyway to return it. What the point of improving my kit if it produces worse images than my old one?
Let's hear what experts think
11-11-2013, 01:35 PM   #4
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QuoteOriginally posted by juio Quote
Hello,

I've bought a K-500 yesterday to replace my Kr and, although it has many improvements, including a better noise reduction, I can't understand one point : the huge degradation of the chromatic aberration between the kr and the k500. I noticed this major issue by taking the same shot in the same conditions : same lens, a DA 35mm 2.4, same aperture 4.0, same speeds with over and underexposures) in low light (home) and with 6400 ISO, taking the shots with 12M pixels for both cameras (I've tried with 16Mp with the K-500, same result), and with and without CA correction.

After many tests, it is obvious that, on this point, the K-500 is outperfomed by the Kr, something I absolutely did not expect. Indeed the Kr's pictures don't show any CA (few with a lot of zoom) but on K-500's pictures, it can be seen without any zoom directly on the K-500 screen!

Did someone notice the same problem? Does it come from the new sensor and the higher resolution? Would it be a problem with my K-500?

Im' considering to return the K-500 to the shop and continue with my good old Kr... the upgrades between the 2 cameras seem really poinless if the CA is so badly managed in the K-500.

Thank you very much for your help.
The K-500 may be front or back-focusing with that lens. Try using live view AF maybe?


Adam
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11-11-2013, 01:41 PM   #5
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Hi again - I just took the time to fully read your post & I realize my reply was pretty redundant . Duh. Does the CA improve when stopped down? Good luck.
11-11-2013, 01:43 PM   #6
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QuoteOriginally posted by Adam Quote
The K-500 may be front or back-focusing with that lens. Try using live view AF maybe?
I've just tried the same shot with live view AF, got the same result.
I must add that I met the same issue with a manual lens.
11-11-2013, 01:55 PM   #7
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QuoteOriginally posted by paulh Quote
Hi again - I just took the time to fully read your post & I realize my reply was pretty redundant . Duh. Does the CA improve when stopped down? Good luck.
Yes it gets better when I step down the shutter speed (going towards overexposure) ot when I step down the aperture. But still can't compare to the Kr results. I use black lines between white drawers to make comparisons. These lines don't have apparent CA on the Kr, event at 2.4, but with the K-500 they are purple.
11-11-2013, 02:06 PM   #8
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QuoteOriginally posted by Adam Quote
The K-500 may be front or back-focusing with that lens. Try using live view AF maybe?
Hi Adam,

It is something I can correct in the AF correction, I'm going try to do something. But it seems to me that pictures from the Kr and from the K500 has the same focus

11-11-2013, 02:19 PM   #9
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Well I tried to adjust the autofocus, no interesting results : the autofocus just got out of focus and the "purple flavor" on the pictures (on the black lines of the drawers) has not disappear.
11-11-2013, 02:29 PM   #10
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QuoteOriginally posted by juio Quote
Well I tried to adjust the autofocus, no interesting results : the autofocus just got out of focus and the "purple flavor" on the pictures (on the black lines of the drawers) has not disappear.
Can you post some 100% crops of the fringing from both cameras?

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11-11-2013, 03:26 PM   #11
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Well here are 2 samples. I don't know how to crop to 100% so I zoomed in and cropped the pictures on the interesting part.

Watching these pics shows me something I haven't noticed before : how the noise treatment is different between the 2 cameras. The K500 has indeed more contrast but is more blurry. The fringe may come from this.
Attached Images
   
11-11-2013, 03:28 PM   #12
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In case it would not be obvious : the first pic is from the K500 (black is purple). The second is from the KR (black is... black).
11-11-2013, 03:31 PM   #13
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I took a picture without any noise reduction, there is still purple...
11-14-2013, 03:35 PM   #14
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Hi all,

After some research on the net, I found that purple fringe is a regular problem with digital cameras. My problem is that on my K-500 it seems obvious. It does not occur on far or small details of a picture, but, as you see on my pics, it affects all the picture (the white part has a purple tint).

Is it normal with the K-500 or do I have a problem with my K-500 and needs to return it? I tried other lenses, same problem each time, and no problem with the K-R.
11-15-2013, 07:22 AM   #15
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QuoteOriginally posted by juio Quote
Hi all,
...It does not occur on far or small details of a picture, but, as you see on my pics, it affects all the picture (the white part has a purple tint).
.
It appears to me that the white balance is different between the two samples. Perhaps you need to adjust the white balance on the K500, and that will make them more equal.

(NOTE: I'm somewhat color blind, so often miss these subtle differences!)

-Joe-
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