D800e Red Oversaturation

Started Apr 15, 2013 | Discussions thread
Tony Beach
Senior MemberPosts: 5,101
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Re: D800e Red Oversaturation
In reply to Steve Bingham, Apr 16, 2013

Steve Bingham wrote:

Tony Beach wrote:

Steve Bingham wrote:

Tony Beach wrote:

michaeladawson wrote:

All I do know is that you have to be very conscious of the red channel because that is the one that will tend to blow out first.

This is very infrequently true.  The green channel blows out first far more often than the red channel.

As for your statement on the red channel being infrequently blown and the green MOST likely - well, I definitely disagree based on my past 30 years of blowing channels.  In fact, Velvia 50 had to be routinely rated at EI (exposure index) 64 instead of 50 - just as a matter of principal -to preserve the yellows.

Film is not digital, so referring to experience with film is absolutely irrelevant.  How about you show some proof of what you are claiming?  Here's some examples of what I routinely see:

I was referring to the yellow in Velvia simply as a way of saying that this "problem" (over saturation) has been around a long time.

The problem is not with the DSLRs we are using, or generally with how they expose the red channel; the problem is one of color spaces, output gamut, and workflow.

So, just for grins, I downloaded your top flower picture and cropped it so I got only the flower. Then I looked at it using PS CS6 and a Histogram as well as Info. My histogram looked NOTHING like what you have incorrectly displayed here.

The histogram I displayed here is from the Raw file -- my only "mistake" was not explicitly pointing that out.

The red channel is pushed hard to the right with a ton of information  - as well as being blown. The yellow was also blown and pushed hard to the left with lots of 0-5 values (0 in blue channel means blown yellows). The  magenta channel, missing yellows and reds, was also left with many 0 values. The green channel, on the other hand, was perfect. No blown greens and a ton of room to spare! Of course even casual inspection should indicate this.

There are three points that need to be addressed here.

The first point is whether or not the camera captured the data, the Raw histogram shown above shows that it clearly did.

The second point is whether or not a "ton of information" was "blown," and even a casual inspection will show that is not the case.  I would also note that having no blue in the pixels does not indicate that the yellows are blown (that will be evident when you look at the crop and histograms thereof below).  What you have failed to account for is that you are looking at a file that has been converted to sRGB color space, and when I was editing it in AdobeRGB color space there was no issue, and the flowers look the same after the file was converted to sRGB (which I do so that it appears as I intend it to appear on the web where most browsers view files in sRGB color space and misinterpret AdobeRGB color space).

To show what is going on in the second point I will show how converting from AdobeRGB to sRGB effects the histogram:

The final point, what all of this leads up to, is output gamut.  If the ink and paper or the monitor can show the colors and detail then there is no issue.  If the output gamut is less than the gamut you are working in then you have an issue that needs to be addressed.  The argument put forward by some in this thread (including you) that the solution is to underexpose the file at the time of capture is what is "dead wrong."

I noticed on your web page you like animals and your Sony camera. Interesting.

Are you trying to make some sort of point by shooting from the hip?  Yes, I currently shoot with an A850, but I intend to switch back to Nikon (which is why I frequent this forum).  The web page I show in my profile has twelve photos (it had thirteen yesterday, that was a mistake because I meant to remove the shot of the horse taken with the A850).  Of those twelve photos, five were taken with my A850, four with my (now sold) D300, and three with my D200 (now converted to IR).  Of those twelve photos, five are of animals, three are of people, two are of bridges (one also having a sailboat featured prominently in it), one is of Half Dome, and one is of a bird of paradise.

I'm something of an eclectic photographer, and I shoot with whatever camera suits my needs and fits in my budget.

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