PDA

View Full Version : Shooting a plasma screen without flicker



Ninja
08-27-2010, 05:38 AM
A recent problem I ran into with the 7D's rolling shutter is trying to shoot a plasma TV screen at 24P. No matter what settings I applied frequency wise on the monitor itself and the shutter speed adjustments on the camera the flicker always persisted. I've gotten to a setting that was rather acceptable and you could even say perfect (I don't recall what it was anymore, but my guess is 60Hz frequency on the TV and something along the lines of 1/60th or 1/30th shutter speed on the camera). The problem then becomes the rolling shutter itself. As long as the camera is locked off everything is fine, but dare you tilt up or down the stretching effect of the rolling shutter causes the TV to flicker.

In theory when thinking about the logistics of how a rolling shutter works it seems a solution is impossible because the monitor and shutter refresh rates would have to match perfectly to be unseen, and this is obviously impossible if you're tilting and the stretching effect occurs because it offsets the synchronicity of the two that is otherwise present in a locked off position, but I'm curious as to whether anyone else encountered this problem and actually DID find a solution, or at least has a theoretical solution that might work. I'd love to put it to the test.

Chris Johnston
08-27-2010, 06:10 AM
I guess the easy way out might be to "corner pin" some footage over the screen.

Ninja
08-27-2010, 08:03 PM
I guess the easy way out might be to "corner pin" some footage over the screen.

That's actually what we ended up doing, and it seems to be the most practical solution. Still, I wonder if there is a live capture solution with camera motion.

kgimedia
08-27-2010, 11:16 PM
That is why all pro video cameras have syncro scan or equivalent. This is one of those rare moments were "fix it in post" is actually easier. That way you can change the content of the screen months after shooting.