Mr. Marchant's fantastic graphs made me think about black shading and the implications of heat.
Setting aside for a moment the fact that I don't quite understand why RED's cameras need black shading when competition does not (or do they?), I got to worrying about the temperature range where black shading applies.
The shooting temperature range appears to be from 40 to 75 degrees Celsius. That's quite a wide range and it feels to me that a black shading done at 40 degrees can not be valid all the way up to 75C (although I could just as easily be wrong about that).
This thinking lead to questions.
- If I perform black shading at 40 degrees and begin a long take, how high can the temperature rise before I might see problems in the image?
- Should I run the temp to 60-65 degrees before black shading if I knew in advance the takes will be long?
- Alternatively, would a black shading closer to 40-45 degrees make sense if I knew in advance the takes will be short (and far apart, with enough idle time to allow for cooling)?
I'd love to see RED introduce a sensor certification feature and some sort of dynamic black shading which would rid us of the need for black shading. Here's how I imagine it might work: (Warning! Non-engineer rambling ahead!)
1) Connect EPIC/SCARLET to a power source with enough juice to run the camera for a couple of hours non-stop.
2) Make sure no light gets to the sensor.
3) Boot camera up, insert REDMAG, enter Maintenance Menu and select "Sensor Certification"
4) The camera begins running a series of automated black shadings at different frame rates, resolutions, shutter speeds and temperatures. This will take quite a while.
5) As a result, a large-ish data file is saved on the REDMAG.
6) Copy the file from REDMAG to your PC/Mac. Download & install a "Black Shading Calculator" software application from RED and load the data file into the app.
7) Based on the data file's contents, the application creates a black shading file which is then copied to a REDMAG and loaded into the camera.
8) The camera now "knows" how its sensor behaves in various different scenarios and operator-performed black shading is no longer needed.
One can dream, right?