ND filters to reduce high exposure

Olivier Metzler · January 24, 2021

Hello everyone,

I have a question about a BTS shot that I saw for a music video (here's the music video: https://www.youtube.com/watch?v=vlBKCwydtPY)
The cinematographer was shooting at:

23.976 fps
180 shutter
T/2.0
EI 800
ND 1.2

Now, my question is regarding the use of the ND 1.2. I understand the use of NDs in exterior locations or when trying to balance an interior with an overexposed exterior, but in this case, the music video was shot on a stage. And so I'm wondering why the cinematographer decided to use an ND 1.2 and shoot at T/2.0, instead of say, have the lighting set for a T/2.0 exposure without the need to use the ND 1.2.

Thanks!

Satsuki Murashige · January 25, 2021

Maybe the DP was planning to shoot some high-speed overcranked shots. Then they just have to pull the ND out to be ready to shoot, rather than having to add more lights. Much faster, and makes the director and AD happy.

Olivier Metzler · January 25, 2021

I hadn’t even thought of that, but that makes a lot of sense!
Thank you!

Would you foresee any other reasons why a DP would overlight then use ND to lower open up again, other than planning to shoot high-speed overcranked shots?

Satsuki Murashige · January 25, 2021

5 hours ago, Olivier Metzler said:

Would you foresee any other reasons why a DP would overlight then use ND to lower open up again, other than planning to shoot high-speed overcranked shots?

Sure, although most would involve changing the ISO/EI or shutter speed, or shooting on location.

1. Perhaps they are trying overpower the natural ambience or practicals in a location they can’t fully control. Say you want a contrasty look with dark shadows, but you’re getting ambient spill from a large skylight that you can’t black out or flag off. The spill is filling your shadows, so you overlight and ND down to increase the ratio between key and ambient fill.

2. Similarly, you’re shooting with fire fx and you don’t want the flames to clip, so you light up everything else to be within the same exposure range. ND just lets you maintain a shallower depth of field at higher light levels.

3. You want to cut the shutter to eliminate motion blur in a later sequence. Same idea as over-cranking, saves time re-lighting.

4. You want the artist’s eye color to pop, so you overlight to get their pupils to stop down.

5. It’s cold inside the studio, and you’re trying to keep everyone warm by turning on all the big tungsten lamps?

Edited January 25, 2021 by Satsuki Murashige