Thread: Quick notes/tips on Red Alert/Redcine DRX

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  1. #1 Quick notes/tips on Red Alert/Redcine DRX 
    Here's some quick notes from me on using Red Alert to get the most dynamic range:

    1- Turn on the histograms. If your shot has values that will be clipped, big rectangles for each channel/color will show up at the right side. Play around with the exposure setting to see these rectangles appear/disappear.

    To get the most information out of your image, you can set the exposure high and keep clicking the down arrow until you see the big rectangles go away. (Another way of doing it would likely be to set exposure = 0, and change the ISO.)

    2- DRX:
    This feature gives you extra dynamic range!! (Kinda.)

    When you white balance, you have to add gain to one or two of the channels so that r=g=b for grey/white/achromatic colors. Normally, you would clip those one/two channels and throw that data away.
    (Or you could do it like FCP and Vegas, where you don't actually clip the channels and things don't look right; but I digress...)

    The DRX feature is similar to the highlight recovery setting in some RAW processors. It won't throw away the data in those one/two channels that were gained up. Instead, it will try to guess what the data in the other channel should be. It will also de-saturate your highlights as a side effect, since it assumes that the blown out highlights are white (and it'll make em white). This tends to work really well- you'll get additional highlight detail, and the de-saturation makes it look like you nailed white balance even if you didn't.

    Where DRX won't work well:
    a- You were off with the camera's metadata white balance. Fix this by setting the white balance via the eyedropper (equivalent).
    b- In the original scene, your blown out highlights aren't all the same color in the original scene (e.g. concert lighting with different colored lights, etc. etc.). In this case things won't necessarily look right... you'll have an effect where you see color/saturation in a bright area and then it transitions into a desaturated color. You'll have to decide which look you want- less highlight detail, or somewhat wacky looking highlights.

    If you were really hardcore, you could probably run multiple passes of DRX with different white balances (appropriate for each light source), and then make a composite of the various passes.

    I hope this helps!
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  2. #2  
    Senior Member
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    Jun 2008
    Thanks Glenn. Much appreciated.

    Robert Castiglione
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  3. #3  
    Senior Member
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    Jun 2008
    Anywhere planes fly
    Thanks, this was helpful
    Jason Comparetto
    Cinema [Oxide]

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