Shooting super clean slow-motion on Epic

[Joshua Hoareau]

Hi all. I presume there are many threads on this but I can't find any for the life of me! If anyone knows the links send em through

Basically I'll be shooting a music video where we'll be having a whole bunch of people in a white room with 50% of people holding balloons full of paint and the rest balloons full of color chalk.
We're doing a big messy color splurge in the white room as it were.
I'm going to be shooting the whole lot in slow-motion but haven't really had to use it much before on my Epic.
What settings would I need to achieve really nice slow-motion without (as best as possible) any motion blur. Just super clean, crisp images.

P.S. we'll also have plenty of lighting.

Thanks heaps everyone

 

[ericyoung]

Motion blur depends on shutter speed. If you decide on the amount of motion blur that's acceptable and set your absolute shutter speed to be that, then set your required Record Framerate, and then use high enough light levels to get the exposure you need.

If you don't have enough light for good exposure at the desired framerate, then you may have to decrease shutter speed and/or framerate as a compromise.

Testing will be a good idea before the actual shoot!

 

[Robino_J]

The common practice for great slo-mo shots is to multiply your frame rate by 2. This will give you the shutter speed needed.

Examples:

24 fps x2 = 1/48th
48 fps x 2 = 1/96th
120 fps x2 = 1/240th

 

[Matt W.]

Simply, the smallest shutter angle/highest shutter speed possible will of course give you the "crispest" look. Balance that against how much lighting you have and what kind of depth of field you need.

Unless you plan on further slowing the footage down in post, you can just use a 180º shutter and expect normal motion rendering when slowed down.

I did a shoot about a year ago at 720fps (forget if the shutter was at 180º or 360º to add much-needed stop) but we were beginning to get a little flicker from smaller electronic ballast Arri HMIs, even undimmed. So I wouldn't push your shutter speed much past 1/500 unless you have tested your lights for flicker, which will be worse on a CMOS sensor than our global CCD. Tungsten units over 5k and HMIs with special-purpose ballasts are safe, anything else try it out first if you can, especially if it is out of phase and thus trickier to reduce in post. Or throw a few out of phase units through the same diff if you're brave, should work in theory to cancel out the flicker.

If you're shooting 120fps, I'd go with 1/240 or 1/480 if you want to play with Twixtor later or you want a slightly choppier/crisper look.

Test if you can. But I'd go for a standard 180º shutter most of the time.