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07-15-2009, 12:16 AM   #1
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k20d blue reproduction and rebates

How successful k20d is when reproducing highly saturated blue, violet and magenta colors. My k200d pretty much fails at it with any color scheme (such as bright and landscape completely over-saturates them, others just give false color).

I'm not expecting absolute real life match for any camera but coherent representation trough whole scene would be nice (now when i turn the saturation down to preserve reds, greens gets very pale).
I understand this is no issue in RAW, but i'm specifically interested in Jpeg.

Another thing is all those rebates i've seen many times in forums. I've never heard of anything like that from local distributors. Is it some kind of US thing, or it is available to all world (europe)?
I have a slight suspicion that things like that never appear here because distributors, or even the actual shop personnel just collect the money themselves.


Last edited by ytterbium; 08-28-2011 at 11:40 PM. Reason: refine title
07-15-2009, 12:33 AM   #2
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I don't know much about blue / violet / magenta saturation, but I've come across one flower here in Slovenia, which is quite common in some places, that has a very, very deep violet colour. Problem is, when I photograph it, that colour turns into a light or middle purple, and is not even close to the depth of the original. I don't know why this happens. But either way, shooting RAW definitely doesn't help. The only way to save that would be some heavy selective editing. =/
07-15-2009, 01:00 AM   #3
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Which flowers?
Gallery of Slovenian wild flowers
07-15-2009, 01:08 AM   #4
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"Detail" in blue sky

I have found blue to be the noisiest colour channel on my K20D. I usually shoot with the "portrait" balance. So long as blue components aren't resolution critical, it is rarely a problem, however it is amazing how large a jpg file is generated when shooting mostly blue sky. All that "noise" or "detail" is carefully preserved at a cost of about eight mb. If there is one item I am happy to have smeared in a photo, it is a big blue sky.

07-15-2009, 01:13 AM   #5
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Can you post a picture of that flower? Just curious..

Have look at color spaces:
Jeffrey Friedl’s Blog Digital-Image Color Spaces, Page 5: Chromaticity Diagrams

The sRGB space is much smaller that that, visible to human eye. And the luminosity isnt even shown there. So those deep colors fall well beyond sRGB boundaries.
But a good sensor, even if nowhere near human eye*, should have larger color space than sRGB.
So if you very detailed color data from the sensor (broad color space, fine graduation - high bit ADC) , you can find a way very precisely and accurately map that color data into sRGB space for best reproduction. Most color modes, i thing just clip the edges by default (whats beyond the sRGB boundary becomes the nearest sRGB boundary value). Avoiding this results in false colors (because those who fit in sRGB has to be moved/shifted/scaled somewhere to fit others in) but produces better graduations and more colour consistency trough the whole scene.

Where can i find any information about the rebates them self instead of ads.

->WHoops.. i was writing my reply so long others already responded.

The blue channel will be the noisiest. I don't know if they are amplified separately, but it must have highest equivalent iso, because silicone imagers are least sensitive to that colour:

http://www.fen-net.de/walter.preiss/e/slomoinf.html

I cant remember exactly why, but there were several more details why blue channel got less light/signal, so more noise.

Last edited by ytterbium; 07-15-2009 at 01:23 AM.
07-15-2009, 01:19 AM   #6
Dom
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Blue is the nosiest channel on any digital camera. I've not found blues and purples to be that much of a problem. If you could give some details on your shooting conditions it will help to shed more light on the problem.
07-15-2009, 01:34 AM   #7
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Its not a problem. It is a question, how well k20d reproduces blues. Just from your experience. Jpeg from camera. Natural color mode. Shooting saturated flowers produces good results or clipped blue/magenta/red blobs?
07-15-2009, 05:21 AM   #8
Dom
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QuoteOriginally posted by ytterbium Quote
Its not a problem. It is a question, how well k20d reproduces blues. Just from your experience. Jpeg from camera. Natural color mode. Shooting saturated flowers produces good results or clipped blue/magenta/red blobs?
I should have read your original post a bit closer. The K20D does very well in the blues.

07-15-2009, 06:07 AM   #9
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You may want to check your white balance when you have issues with flower colors. I guess it's not easy for the camera to found the correct balance with colors that so intense.
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