Timecode sync with shutter

[swellison]

When the RED is synced to an external timecode, does the shutter open at the beginning of each frame? For example:

If you're running 24fps, then each frame lasts 1/24 of a second. So, if you're at timecode 01:00:00:01, then only 1/2 of the period of time at this frame is being exposed (given a shutter of 1/48). Does this exposure occur during the first half of this frame or the second half?

 

[Cail Young]

As far as I'm aware there's no guarantee either way, and indeed I've seen shots of TC slates showing two different frame numbers - i.e. exposure is bridging two TC frames.

The only way to guarantee frame timing is to genlock.

 

[swellison]

what do you mean by genlock? im using an external timecode generator - isn't that genlock?

 

[Cail Young]

what do you mean by genlock? im using an external timecode generator - isn't that genlock?

No. Genlock is a frame synchronisation system using (in HD video and for the RED ONE) "tri-level sync" and you'll need a specific generator for that. The Denecke SB-T is a rare example of a device that generates both a TC signal and tri-level sync.

 

[Stuart English]

Sync

Sync

Yes, that is true, but the question is when does the external timecode generator change its value relative to when the camera captures its next frame?

Both can be running at exactly 23.976 fps, but one may be running a fraction later than the other (i.e they are in sync but are out of phase)

That's why running Genlock and Timecode into the camera is the best sync solution.