I've been shooting a lot of little pickups and one-day shoots with my BlackMagic.
Recently, I tried to setup a lighting scheme where the background was at least 2 stops under the talent.
The talent was lit beautifully at a 4/5.6 split. Let's call it 5.6 for the sake of argument.
The "sun coming through window" read 2.8 on the meter, and the shadow area outside that read at most 1.4.
I've also been reading a lot about what others are doing in their lighting setups and I've either confused myself, or learned something wrong.
What is a full stop?
I guess I should have tried to light the background SIX stops down from the talent, as on the camera sensor it never did read how I wanted it, even though it looked good to my eye.
I keep hearing master cinematographers say things like f2.8 > f4 ' is a full stop ' , Except when I read about the theory and practice it is not. ISO and Shutter speed double, which is easy.
And even mathmatically, 2.8 is not double or half of 4. Is it just semantics?
I recently watched a video where the DP set the lens to f4, liked the look but wanted to open the lens up one stop so he threw in a ND.3, and opened to f2.8 - It looked good on the monitor, and he was happy, but I was not. Did he not just cut 1/2 a stop?
Why is it that some DP's call each half number a "full stop" and some call each doubling (f2, f4, f8) a "full stop" and who is correct?
I can tell you that it sure doesn't look like I let twice as much light in when I open up from 5.6 to 4, the math doesn't seem to support that either, but math is hard.