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02-27-2008, 05:22 PM   #16
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QuoteOriginally posted by Katsura Quote
Interesting observation from the pics:

The K20D noise handing seem to supress the red channel FAR more than the blue and green channel - in fact, the blue looks so pronounced I wonder if they did anything to supress it at all?

The A700 chroma noise supression seem to evenly apply to all 3 channels.

So, Pentax = heavy handed with red chroma noise and ignored the blue? What is the thinking behind such an algorithm? Is there any scientific study showing this is more pleasent to human eyes?

(P.S> The noise patten on K20D ISO6400 shot looks similar to my SonYEricsson camera phone - lots blue noise and no significant red chormo noise LOL!).
That could be reflecting the white balance, no? I haven't analyzed the JPEGs, but I think it's not safe to make this kind of conclusion from a posted JPEG. Anyway, it looks way better than the Alpha, and with less NR. Someone could test for resolution in the blue channel in the future...

And a request: Chris, would you care to edit your post and replace the pics with a link? It's destroying the layout, it's hard to navigate, and I hate having to reload the pics when I empty my cache. Thank you! :] edit: nevermind, we are on page 2 now!

02-27-2008, 06:58 PM   #17
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Chris, which yellow of spray can is the 'real' one like what your eyes saw? Me thinks the K20D should definitely be turned down off vivid for this comparison; look @ that yello of the spraycan cap bleed. Ironic, isn't it!?!? ...that that doesn't "test well". <big grin>

Boy, that ISO6400 is a let down on the K20D. I now understand the "unacceptable" rating it got in that mag we all know about. I'll still take the camer tho.

Last edited by m8o; 02-27-2008 at 07:05 PM.
02-28-2008, 02:22 AM   #18
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QuoteOriginally posted by Katsura Quote
So, Pentax = heavy handed with red chroma noise and ignored the blue? What is the thinking behind such an algorithm? Is there any scientific study showing this is more pleasent to human eyes?
Just a guess, but the blue channel is receiving markedly less information than the other two, with the red receiving less than the green by a fair amount. All of this is due to the density of the tricolor filtration on the photosites. Perhaps this algorithm maintains more blue channel signal (as opposed to noise) than any further reduction in the blue channel would?

Again, just a guess...

02-28-2008, 05:33 AM   #19
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I am not sure what everyone else sees.
The A700 WB is warmer and would therefore not be stressing the blue channell as much as the Pentax K20D.
The K20D image 6400 retains more detail because it does not apply RAW Noise reduction. just look at the Porche. Also I wonder what would happen if we blew the 12MP image to the same size.

Overall I would require to put both of these high iso images through Noise reduction software, I know I would like to start off with the more detail, the noise can be dealt with more effectivley if its not already smeared.

04-21-2008, 09:36 AM   #20
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What is up with the blown yellow in the K20d shot? Check out the blower can's plastic top and compare to the a700, d300, 40d. All of the other cameras show clearly that the yellow plastic is encased by semitransparent plastic. Not so with the k20d. Is this some sort of photographer error? Or does the pentax just have problems with yellow? I'm no expert (just someone who really wanted the k20d to be the dslr I've been waiting for), but this looks like it may be a dealbreaker!

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