Shower Heater commercial

[Jason Joseph]

Hi all

we have a commercial to shoot next week on the red. its going to be a shower heater commercial, where a model is showering, we're building a shower set in studio, basically a L-shaped shower stall. We want to shoot slow-mo and the look is supposed to be like the Japanese "super white" looking commercials. Here are some references

http://www.youtube.com/watch?v=xfQ-OdEuEIY&list=PLD71827CB0088E0F4 (for the look)
http://www.youtube.com/watch?v=qwWabrUKmgk&list=PLD71827CB0088E0F4
http://www.youtube.com/watch?v=L0zKV9uljPM&list=PLD71827CB0088E0F4
http://www.youtube.com/watch?v=QAD5ZLt0M4o&list=PLD71827CB0088E0F4

So question is how much more light will we need to shoot slow mo (60-90fps) ? Never shot slow mo in studio before. At the moment we were going with 2x 4ft kinos up top above the shower, and 2x 1.2k HMI through frames on the sides with a 2.5k HMI Par when necessary.

Any advice would be great! thank you all in advance

 

[Mark Wilkinson]

This can be calculated with photometrics assuming you can narrow down some variables:

What diffusion are you putting into the side frames?

Are the top kinos 4x4 banks or just 2x 4' tubes?

What ISO are you shooting, what shutter angle and do you have a target t-stop?

 

[Jason Joseph]

hey mark
thanks for replying
diffusion will be 216 lees
4x4 kinos
iso 320
shutter angle not sure will do some on set tests
f2.8 - 5.6

any recommendations?

 

[Mark Wilkinson]

Well,

If your 2 kinos are about 1 meter above the subject, they will give you about 480 foot candles total illumination.

If you put your 1200 par about 10 feet back with a wide lens, that'll give you about 1700 FC, then through 216 will cut about a stop and a half, so your side lights will be about 635 FC each - and you'll want to keep those a little on the spicy side judging from your sample.

Maybe you use your 2.5 k par as front fill - bounced and then through diffusion to taste.

If you figure at t4, 320 ASA you need 65 FC for key, then you lose 2 stops for overcranking to 96 fps, that means you'll need 260 foot candles for key. Your side lights are giving you about a stop and a half over that - not as spicy as it might be, but enough to keep them bright. You've even got enough wiggle room on the kinos to throw some opal on them if you like, too.

So the short answer is yes, you should have enough light for 96 fps - IF you leave the shutter at 180 - though you may have to make your shutter angle 288 to avoid flicker on the HMIs which will buy you some more light. In any case, keep an eye out for flicker on HMIs at high speed on Red - you also may need to change your timebase to 24 (it's a Red bug).

Check my math anyone?

 

[Jason Joseph]

thanks mark
we will give it a shot