Thread: Blackshading--WHY?

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  1. #1 Blackshading--WHY? 
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    One of the big reasons I ordered a Raven is because I really hate black shading. I was under the misconception that the DSMC2 bodies can do a sort of auto calibration based on your exposure time and working temperature. I've just realized now (after some research) that this is not the case. While DSMC2 cameras can calibrate multiple exposure times at once (awesome!) they cannot handle varying temperatures without another black shade (bummer). So I have a couple of questions.

    1. What kind of tolerances do these cameras have? If I go from a 90 degree environment to a 65 degree environment, will I be screwed without a black balance? With my Scarlet MX I'm seeing the yellow or red "T" even with a variation of about 15 degrees.

    2. Why in the world do we have to do this on Red cameras? I've been on plenty of shows with the Alexa, and we never blackshade or anything like that with the Alexa. What is it doing that the Weapon/Scarlet-W/Raven does not?
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    Senior Member PatrickFaith's Avatar
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    I keep the fan setting on auto at 37 (and I do the bs at that temp), so that Black Shade seems very stable between 35 F to 92F. I think the bs is more important if your drastically changing the shutter/fps, which I hardly ever do since I am 99% of the time at 24 fps / 180 shutter. If your in hotter environments you might want to put the auto fan speed higher then bs at that, then you can focus on the creative part and not mess with bs.
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    Just a question: if you keep the fps base project and you change the fps at lets say 60(vary speed) do you need to do the bs?
    thanks
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    Quote Originally Posted by Luca Volpe View Post
    Just a question: if you keep the fps base project and you change the fps at lets say 60(vary speed) do you need to do the bs?
    thanks
    The only things that affect your blackshade are temperature and exposure time. Since changing the frame rate would entail changing the exposure time, yes you would need to blackshade again. But from what I understand, the new Auto Blackshade feature will do a calibration for multiple exposure times at the camera's current temperature. In that case you would just need to bring the camera up to temp, do an auto BS, and you could switch between 24 and 60 all you want. It's when the temperature changes that you might have an issue.

    My big question here is really why we even have to worry about this. Sony and Arri seem to have it figured out...
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    Senior Member Christoffer Glans's Avatar
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    I haven't done an auto black shade on mine yet, but the theory is to do an auto-cal in different temperatures so that if you shoot in cold weather, you have one auto-cal set and if you shoot in-doors or in "normal" temperatures you have another, then one in hot temperatures like non-air cooled studios or deserts. You really would only need to have three sets of auto-cals to choose by and... how many times would you really choose between those?
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    Senior Member PatrickFaith's Avatar
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    Quote Originally Posted by Kenneth C Merrill View Post
    The only things that affect your blackshade are temperature and exposure time. Since changing the frame rate would entail changing the exposure time, yes you would need to blackshade again. But from what I understand, the new Auto Blackshade feature will do a calibration for multiple exposure times at the camera's current temperature. In that case you would just need to bring the camera up to temp, do an auto BS, and you could switch between 24 and 60 all you want. It's when the temperature changes that you might have an issue.

    My big question here is really why we even have to worry about this. Sony and Arri seem to have it figured out...
    hmmm... You don't respond to me, then you belittle red on a obvious question that can be easily googled. Might be your not ready for RED.
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    Quote Originally Posted by Kenneth C Merrill View Post
    One of the big reasons I ordered a Raven is because I really hate black shading. I was under the misconception that the DSMC2 bodies can do a sort of auto calibration based on your exposure time and working temperature. I've just realized now (after some research) that this is not the case. While DSMC2 cameras can calibrate multiple exposure times at once (awesome!) they cannot handle varying temperatures without another black shade (bummer). So I have a couple of questions.

    1. What kind of tolerances do these cameras have? If I go from a 90 degree environment to a 65 degree environment, will I be screwed without a black balance? With my Scarlet MX I'm seeing the yellow or red "T" even with a variation of about 15 degrees.

    2. Why in the world do we have to do this on Red cameras? I've been on plenty of shows with the Alexa, and we never blackshade or anything like that with the Alexa. What is it doing that the Weapon/Scarlet-W/Raven does not?

    1. DSMC2's entire ventilation system and general thermal architecture are different from DSMC bodies. Higher tolerances and better cooling are part of what the new system does well. It's hard to know exactly what ranges a given calibration will play well with, but I've had warm days into cool nights that worked fine. Extremes variations are really what you need to be on the lookout for.

    2. RED's Sensor Calibration process is part of the procedure to capture the highest quality possible images out of the camera. Arri's method of Defect Pixel Correct (DPC) and Black Balancing come in the form of image processing via hardware. It's a different technique than RED, Sony, and Panasonic utilize.


    Quote Originally Posted by Kenneth C Merrill View Post
    My big question here is really why we even have to worry about this. Sony and Arri seem to have it figured out...
    Sony has APR, or Auto Black Balance on the F55.


    The longer answer to much of this is maintaining high quality pixels, in the case of RED a lot of high quality pixels, as well as examining and counter acting the fixed noise pattern. I've met more than one individual who has never Black Shaded their camera nor paid attention to the temperature and exposure notifications. While you can do whatever you want, don't be that guy. Run a Sensor Calibration ahead of a shoot during prep or at the beginning of the week or month. Whatever floats your boat. If you suddenly are in the arctic, you should likely do that again. Then if you find youself back in Death Valley, yep it's a great idea. And somewhere between the heat and cold environments, there's firmware updates. After you install a firmware, you should run a Black Shade.
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    Senior Member Gene Sung's Avatar
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    Quote Originally Posted by Christoffer Glans View Post
    I haven't done an auto black shade on mine yet, but the theory is to do an auto-cal in different temperatures so that if you shoot in cold weather, you have one auto-cal set and if you shoot in-doors or in "normal" temperatures you have another, then one in hot temperatures like non-air cooled studios or deserts. You really would only need to have three sets of auto-cals to choose by and... how many times would you really choose between those?
    Would this work?

    If someone who really knows what they are doing like Phil Holland or even Red, were to offer a set of good Auto Black Shades I would gladly buy it off them.

    ABS in a walk-in refrigerator to simulate cold winter, another for mild Autumn temperatures, my S-W came with a stock 40 Celsius which I am assuming is for the average room temp, then a final ABS done in a dry sauna to simulate shooting in the hot desert?

    The camera stores 4 profiles and it seems like BS would be much less an issue as you just have to pick one of the trusted ABS done by a Red technical expert then a majority of shutter speeds and temps are covered.
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    Quote Originally Posted by Gene Sung View Post
    Would this work?

    If someone who really knows what they are doing like Phil Holland or even Red, were to offer a set of good Auto Black Shades I would gladly buy it off them.

    ABS in a walk-in refrigerator to simulate cold winter, another for mild Autumn temperatures, my S-W came with a stock 40 Celsius which I am assuming is for the average room temp, then a final ABS done in a dry sauna to simulate shooting in the hot desert?

    The camera stores 4 profiles and it seems like BS would be much less an issue as you just have to pick one of the trusted ABS done by a Red technical expert then a majority of shutter speeds and temps are covered.
    This does sound like a good idea, but I'm pretty sure the black shade need to be specific to YOUR sensor. The last thing you want is a mismatch between the calibration and your camera, which would look horrible.

    Somebody chime in of Im wrong here.
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  10. #10  
    Senior Member Gene Sung's Avatar
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    Quote Originally Posted by Kevin DeOliveira View Post
    This does sound like a good idea, but I'm pretty sure the black shade need to be specific to YOUR sensor. The last thing you want is a mismatch between the calibration and your camera, which would look horrible.

    Somebody chime in of Im wrong here.
    ahhhh... Got it. That makes sense. Well, I'm going to find a walk in fridge today, LOL.

    well, if this would work, once I learn how to Black Shade correctly (just got my S-W), I'll probably do something like this.

    well, Auto Black Shade sounds awesome EXCEPT it says it can take up to 1 hour. On set, that could be a real issue, which is why some pre-made Auto Black Shades would be awesome.

    if Red could somehow get Auto Black Shading to around 10-15 minutes, this would be a much smaller issue.
    Last edited by Gene Sung; 04-25-2016 at 07:06 AM.
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