Posted 07 October 2009 - 04:10 PM
I have a shoot coming up on the Red. It's all day exteriors and for some reason or other I wanna shoot without a matte box and hence no NDs and add to shooting at T2ish. So the question is how low can I rate the ISO on the Red and what happens ???
Posted 07 October 2009 - 04:50 PM
Posted 08 October 2009 - 02:21 AM
The lower you rate the ISO, the less exposure headroom you will have. The camera sensor's nominal rating is 320 ISO, so if you rate at 160, you will have 1 stop less range in the highlights. DP Art Adams suggests the sensor has 3.5 to 4.5 stops of overexposure range under 5500K and 320 ISO: http://provideocoali..._torture_tests/.
So the question is how low can I rate the ISO on the Red and what happens ???
That might be okay if you can control your highlights with silks and such, but most day exteriors will have highlights well over that. So by rating the camera at 160, you will only have 2.5-3.5 stops over middle grey before clipping. That's not much, a white shirt under flat, soft light will be 2 stops over.
You can always tape flat NDs to the lens in a pinch, or use drop-in rounds in a metal clip-on shade, or tape a bellows with a 138 back to the lens. Or just cut the shutter. Lots of options.