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09-27-2011, 12:18 PM   #1
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Red Channel overload!

So I did see this before, but not to this extend. Overload on the red channel.

original image from my camera.
https://dl.dropbox.com/u/20195454/_K5I2795.jpg
This is made with K-5, DA*60-250, -0,3 EV to prevent this. Dynamic Range expansion set ON (or is this the killer of my red channel?)

Anyone ideas or experiences?






Last edited by RonHendriks1966; 09-27-2011 at 01:09 PM.
09-27-2011, 12:59 PM   #2
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I'm unclear on the problem. Probably just missing something. :-)
The grayscale, and the linked original look fine. It looks like whatever was used to bring up the exposure pushed the red higher. Looks like you just have to drop the reds a bit, perhaps in selective areas. (I see the white is just starting to blow out as well with the adjustments, as well)
09-27-2011, 02:10 PM   #3
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I constantly fight the reds with my K5, I don't recall this much trouble with my K20D and reds. They blow out fast and they blow out strong. For my Cardinal bird shots I have had success in shooting in Muted mode and then adjusting the color in processing, but this is not effective in many other situations. Maybe someone will have a better plan? The problem is...when they are blown...they are gone, you can't recover them if they are too far right.
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09-27-2011, 02:16 PM   #4
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What does the RAW file look like?



09-27-2011, 02:23 PM   #5
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Jeff, on my part, the Raw file looks worse than the Jpeg...like maybe the K5 has tried to correct the red blow out in the Jpeg result? If that makes any sense?
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09-27-2011, 02:38 PM   #6
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The best method I've heard of for working around this is to underexpose sufficiently for the red channel to stay intact and then bring up things back up in post, where the curves can be worked with on an individual basis if necessary.
The very long range of the K5 sensor should make this very workable, but I haven't been in a situation yet where it's been necessary for me to try.
If it's any consolation, reds have been a problem in colour photography since long before digital imaging.
09-27-2011, 02:40 PM   #7
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QuoteOriginally posted by JeffJS Quote
What does the RAW file look like?

Took this set in jpeg only.

It is only with bright colours (red, yellow, green) that I see this and the red channel is very easy to blow out to my feelings.
09-27-2011, 02:43 PM   #8
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QuoteOriginally posted by RonHendriks1966 Quote
Took this set in jpeg only.

It is only with bright colours (red, yellow, green) that I see this and the red channel is very easy to blow out to my feelings.
Then where did the different versions come from?
Again, the red in the "original" looks great. The grayscale also looks great.
Was the topmost posted image with the blown out red processed through software? That would be my guess as the problem.

09-27-2011, 02:54 PM   #9
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QuoteOriginally posted by RonHendriks1966 Quote
original image from my camera.
https://dl.dropbox.com/u/20195454/_K5I2795.jpg
QuoteOriginally posted by amoringello Quote
Then where did the different versions come from?
Again, the red in the "original" looks great. The grayscale also looks great.
Was the topmost posted image with the blown out red processed through software? That would be my guess as the problem.
Well maybe my processing in Lightroom isn't up to where it should be at the time.

The link is the original file from the camera. It seems okay, but there is texture in the white shirt where it is missing in the red shirt!
09-27-2011, 02:54 PM   #10
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QuoteOriginally posted by amoringello Quote
Then where did the different versions come from?
Again, the red in the "original" looks great. The grayscale also looks great.
Was the topmost posted image with the blown out red processed through software? That would be my guess as the problem.
The Red is blown out on the left players shirt and the top part of the right players collar. The grey scale demonstrates this where it is just flat and paper-like looking. There is no detail. It looks ok but I wouldn't call it 'great'. To keep Reds (and yellows) in check, I typically underexpose by a stop and bring the rest up if necessary in post processing.

09-27-2011, 02:58 PM   #11
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If you are using Lightroom to push up the exposure, you're going to have to use the brush tool to bring it back down in the reds.
Just more give and take in photography. :-) Although Lightroom is great in many ways, it can only do so much when you're pushing the exposure boundaries. This sort of problem might be better controlled in Photoshop or other bigger,badder program, but only because you can better mask off and control were changes are being made.

(You might also drop exposure a tad in the shoulder of the girl in white, as it is getting blown out there... although honestly not out of acceptable range... its not an important part of the photo... but its noticeable.)
09-27-2011, 03:03 PM   #12
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QuoteQuote:
but there is texture in the white shirt where it is missing in the red shirt!
Sorry, sort of glossed over this... but yeah... reds can do that.
Nothing says all colors reflect the sun equally or captures the same by the camera. :-)
The white shirt also appears to be more oblique to the camera and may not be reflecting as much direct light as the red shirt.
Although I'm no expert on such things thats how it looks to me.
09-27-2011, 03:14 PM   #13
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Ken Rockwell would loooove that pic
09-27-2011, 03:56 PM   #14
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QuoteOriginally posted by cali92rs Quote
Ken Rockwell would loooove that pic
I am guessing for the +111 level saturation.
09-27-2011, 04:03 PM   #15
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QuoteOriginally posted by rawr Quote
I am guessing for the +111 level saturation.
He calls it "wild colors"
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