Flicker on video taken with a DSLR camera.

[prunkdump]

Hi !

I try yo use my canon 550D dslr camera in video mode but on certain scene the result seems very jerky so the video isn't acceptable. Here a shoot that demonstrate the problem :

http://dl.free.fr/iNwtUAQZk

I first thinks that this is due to the rolling shutter (on dslr the entire frame is not taken in one time but line per line) so I try to make the scene by a time lapse :

http://dl.free.fr/q8Nxy981i

But the problem is still here.... Maybe my screen refresh rate is to slow to play a scene like this (60 hertz) ? Do you see the problem with your screen ? This type of scene need to be avoided ?

Thanks !

[hech54]

My DSLR also takes video. Having said that....I'd rather grab my Canon portable/pocket camera of my iPod Touch to take video. DSLRs are "not ready for prime-time" when it comes to video.

[smrpix]

Assuming you are referring to left/right strobing on pans, either pan slower or slow down your exposure time (NOT your framerate.) I'm not seeing any jelly-roll so I think you are misdiagnosing the line by line issue.

[prunkdump]

Yes ! This is that strobing effect on edges that I find very disturbing ! You'r right, there are no jelly, the second video is taken with a series of pics.

I have tried to take the scene with a 1/30 shutter speed but the effect is still clearly visible .... Maybe there is too much constrast on this scene ? Is this problem specific of DSLR camera ?

Is there a post processing effet that can reduce the problem ?

Many thanks for you reply.

[jagabo]

24 fps isn't going to give you smooth motion. You have to use film shooting techniques, slower pans, reduced depth of field, lower contrast, etc.

Your video sped up to 30 fps, then motion interpolated to 60 fps (view on a 60 Hz monitor).

[Cornucopia]

You should also use at least (most?) a 180degree shutter (aka if your framerate is 30FPS, your shutter should be 1/60th second) for things to look decent. On low end consumer cameras, you can't even get to adjust this, so you might be stuck until you upgrade.

Scott

[smrpix]

Is this problem specific of DSLR camera ?

Is there a post processing effet that can reduce the problem ?

If it makes you feel any better, this is a problem that affects the finest Panaflex and Arriflex motion picture cameras with superb lenses and modern film stocks.

(Now that you've seen it in your own videos, you will notice it in every movie you watch.)

The issue is the relationship of frame rate to shutter speed to pan speed. The solutions are to slow down the shutter as much as possible to "motion-blur" the edges and/or slow down the pan rate so the edges don't jump as far from frame to frame. (For that matter you can speed up the pans to introduce blur as well.) I'm all but certain you can manually adjust the shutter speed on the 550D in video mode.

You can try adding a directional motion blur after the fact -- but it will affect everything. (jagabo did a nice job of decreasing the edge strobe, though his technique introduced new artifacts into the wall surface -- there's always a trade-off. The best option is always to shoot it well in the first place.)

[jagabo]

My video wasn't meant as a solution to the problem. Just a demonstration of how higher frame rates look much smoother. I would have just doubled the rate to 48 fps but that has another type of jerkiness on a 60 Hz computer monitor.

[smrpix]

jagabo, didn't mean it as a criticism -- I should have used better wording. I apologize.

I was a little too eager to reinforce the idea that shooting it carefully in the first place is usually the simplest solution.

[jagabo]

jagabo, didn't mean it as a criticism

I didn't take it that way. I just wanted to be sure the OP knew I wasn't suggesting it as a fix.