Matching frame rate for precise Opacity

[Lee M]

I am trying to record 2 identical shots that I can mask certain parts using the Opacity feature in premiere. I can't seem to pinpoint the exact camera location to a single frame, it is slightly off between the 2 videos which I am assuming is due to both videos being recorded seperately and 24 frames per second not being precise enough. Other than keeping my camera recording for both shots, are there any tricks to getting this right? Perhaps this is what the pre-role option is for? Using the Red Epic Dragon.

 

[Hal Long]

Unless the camera is locked off or you're using a motion control rig, you won't have "identical shots." That said, if you're compositing elements from one shot into another @ 24 fps and find the actual frame rate isn't high enough, then you may need to shoot at something higher like 48 or 96 fps to get the motion parity you need. Then, once the frame/motion is aligned you can change the speed so the clip plays back @ 24 fps.

Since the videos were "recorded separately", I guess that would mean they weren't shot multi-cam with synced cameras or genlock.


Pre-roll only provides a buffered recording so that once record has been enabled the preceding buffer is also captured. This is very handy for news and doc shooting where you start the record after something has actually happened.

 

[Justin McAleece]

You're probably looking at an issue that Genlock would've solved unfortunately.

 

[Marc Wielage]

I know of 3D post companies that specialize in locking together two separate images that have various alignment problems, but it's not cheap.

What I would suggest is you find a way to pin the two images together and use some kind of image-warping software in Mocha or After Effects or something like that. A good VFX person would find a way to make it work. If there's a non-synchronous shutter issue due to lack of genlock, that's a tough problem for which I have no advice. It might be technically possible to "paint" in the missing visual information, kind of like VFX animation, but it'll be time-consuming and costly. It is possible to do.