Canon 6D sensor & the red channel

Discussion in 'Canon EOS' started by tim_carroll, Jun 4, 2016.

  1. About 15 years ago I was doing a lot of work with a Canon XL-1s digital video camera and I remember the sensor had a tendency to really over power the red channel, something we always needed to tone down in post production.
    Well I just got my first Canon digital still camera (a Canon 6D) and am noticing the same thing is happening. Is this normal with the Canon digital sensors? Do they all punch up the red channel a bit?
    I am shooting in RAW only, and working the files in post, but I am noticing the red channel really needs some toning down in my images and was wondering if this is common?
    Thanks for any and all input.
    Best,
    -Tim
     
  2. I always find the red channel to be weak and I replace it with green channel very often.
    The oversaturated reds are common in digital cameras and are stronger with Nikon from my experience.
    When making portraits I often desaturate reds though.
     
  3. Is there a way to desaturate the red channel in camera, before the data gets into the RAW files?
     
  4. Tim, yes you have white balance compensation called WB Shift/BKT in Shooting Settings 3.
     
  5. Thanks Igor.
     
  6. It also helps to set the Pic Style to Neutral so your Histogram reflects exposure of the individual channels more accurately. Although the red channel is easier to blow out than the other channels, the 6D's red channel is better controlled than some of the prior EOS I owned. For me, the red channel was only problematic when I shot red and orange flowers so I use a wee bit of EC and eye the Histogram regularly. Human skin has a lot of reddish tones and desaturating the red channel even a little makes them resemble the undead...
     
  7. Thank you.
     
  8. When desaturating reds in skin tones to get natural skin look, you can add cyan in reds by adding blue and green (actually removing magenta and yellow) and blue in yellows (actually removing yellow) using selective color tool. Much better than using hue/saturation and picking reds.
     
  9. Yes, it's common.
    Tim, yes you have white balance compensation called WB Shift/BKT in Shooting Settings 3.​
    He's shooting raw. The camera's white balance settings will affect the initial rendering of the raw file on the lcd and in some software, but it has no effect on the raw file itself.
    Is there a way to desaturate the red channel in camera, before the data gets into the RAW files?​
    Not if you are shooting raw. However, it is essential that the red channel not clip. So set the picture style to faithful and set the camera to show all three histograms. Reduce exposure until the red doesn't clip. Faithful is better than neutral for this purpose because it has no saturation boost, while neutral has a low saturation boost. See this link from Canon Japan.
    There are several things one can do in postprocessing, apart from saturating. For example, increasing contrast using most tools, such as the default RGB curves tool, will increase saturation, and that will make the effect worse and can lead to a loss of detail. A simple alternative if you are using photoshop is to use the luminosity blend mode for all tonality adjustment layers. Working in LAB space can accomplish the same thing but is more of a change from most people's normal procedure. I've read that the same is true of sharpening, but I haven't checked that out yet.
     
  10. Dan, if you use ACR and Adobe Standard profile it combines contrast of Camera Standard and lower saturation of Camera Neutral.
    Faithful is very flat and you have to use curves to get the look, in RGB or Lab space. I used to use camera Faithful for many years but now I prefer Adobe Standard.
    In RGB you can always use curves in color mode for color and in luminosity mode for contrast.
    If you use DPP I am almost sure that WB Shift is there.
     
  11. Here is a comparison of Canon and Adobe camera profiles.
     
  12. Spearhead

    Spearhead Moderator

    If you use DPP I am almost sure that WB Shift is there.​
    This happens because DPP reads the WB setting and adjusts the viewed file.

    As Dan says, there is no way to change the data going into the raw files.
     
  13. Dan, if you use ACR and Adobe Standard profile it combines contrast of Camera Standard and lower saturation of Camera Neutral.
    Faithful is very flat and you have to use curves to get the look, in RGB or Lab space. I used to use camera Faithful for many years but now I prefer Adobe Standard.​
    My point was that if you want to make sure you are not clipping the red channel, you should use faithful so that the histogram on the camera is as accurate as possible. It will come closest to what you would get with no additional saturation. I was not recommending it because of any effect on the raw file. It has no effect on the raw file.
    The picture style you pick is irrelevant if you are reading the photo into Lightroom. If you use adobe standard, as I do, LR will render the image with that algorithm, regardless of how you have the picture style set.
    If you use DPP I am almost sure that WB Shift is there.​
    That may be so, because DPP uses more of the image's metadata to render the raw image. However, the camera settings still don't alter the raw file; they simply give DPP a starting point for rendering.
     
  14. "The picture style you pick is irrelevant if you are reading the photo into Lightroom"

    Actually you can pick camera picture style in lightroom Dan.
    00dzZs-563600284.jpg
     

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