Technical Question - Shutters + High Speed at 23.976

[Adam Etherington]

Hey guys. I have a quick tech question. I am shooting something in the EU for US Broadcast.

The US Post House have requested we shoot at 23.976, which of course makes perfect sense.

However, I am wondering whether I need to use a 172.8 (standard for 24fps) shutter or a 172.6 shutter (which would give 1/50th of a second)? in order to avoid potential phase issues with the 50hz electrical system in the EU?

Also, what frame rates do people usually overcrank to when shooting high speed on a base of 23.976?..... 47.952 fps? Or should I jump to 48? I am aware they may shoot dialogue at high speed then ramp back down for sync for portions of a take... So I am guessing it makes sense to double the frame rate then halve it back to make the speed change easier at the far end?

Any informed feedback would be gratefully received with thanks.

 

[Ulf Krentz]

Adam you may find this helpful:

http://www.red.com/tools/flicker-free-video

Cheers, Ulf

 

[Adam Etherington]

Hi Ulf,

That is very helpful. Thank you

 

[John Marchant]

Its your base frame rate more than your shutter speed that presents a flicker issue for regular shooting. 23.98 with 50hz mains can be an issue depending on the type of lighting, and shutter speed won't fix it. What's occurring is that the start time of each frame, regardless of for how long it is exposed, is not synchronised with the mains frequency.

 

[David Battistella]

This might also help.

http://www.reduser.net/forum/showthread.php?110198-Slow-motion-best-practices&highlight=

Battistella

 

[Adrian Weinbrecht]

Very good point John

What would you recommend as a Timebase for productions that are being filmed in the USA and Europe and then the footage mixed?

Most people seem to recommend 23.967

Any thoughts?

Adrian