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Hey everybody,
I have a studio car shoot coming up and we’re shooting very high speeds (500 fps – 1000 fps) to capture rain and flower canons on the car.
-> does anybody have any tools/ ways/ apps to calculate more or less how many fixtures we want to put in the softbox? I am for sure thinking bigger is better, but there is a budget off course. At the moment we are thinking 28x Vortex8, but clearly I want to know is this total overkill or just enough? There should be simple mathematics to this right?
Height softbox to car = 7-8m
Softbox Size = 10m x 7m
Thinking about full grid or magic clothSo in short, how do you calculate a certain stop at a certain distance for studio shoots?
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That’s about a 5-stop light loss so you look at the photometric data for the light and figure out how many foot-candles you need to shoot at, let’s say f/2.8 at 800 fps or think of it as shooting at f/16 at 25 fps.
The old rule of thumb is that you need 100 fc to shoot at f/2.8 / 24 fps / 180 degree shutter / 100 ASA. So that’s like f/8 at 800 ASA if you have 100 fc. So to get 2 more stops of exposure for f/16 at 800 ASA, you’d need 400 fc. Then you’d be shooting near an f/2.8 at 800 fps at 400 fc. I think.
Let me see if i understood.
F/2.8 to F/8 is 3 stops less. So you need 3 stops of ASA more to compensate (from 100 to 800).
2 stops more from that means 4 times the light.
So 100 fc x 4 = 400 fc (for f/8 at 800 ASA).
Is It correct?
At 24/25 fps at ISO 100:
100 fc = f/2.8
200 fc = f/4
400 fc = f/5.6
800 fc = f/8
So with ISO 800:
100 fc = f/8
200 fc = f/11
400 fc = f/16
You lose 5-stops going from 25 fps to 800 fps, so to shoot at f/2.8, you need to light for f/16 so that once you lose 5-stops by going from 25 fps to 800 fps, you’re down to f/2.8.
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