Is it possible to speed up camera movement, without it looking sped up?

[Ryan Elder]

Okay thanks, this was the idea that I was going to do but wanted to do tests without actors first to see if it will work. But even if there are no moving subjects or people in the shot, it still looks like it’s been sped up and not natural.

Here is a test I did. The first is sped up without motion blur, and the second has the motion blur added. But it still looks like it’s been sped up, even if there are no people in it:

https://www.youtube.com/watch?v=8yOAtp43Ko0

Or is it just me?

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[Mark Whitney]

How are you doing the speed up?

The Re:Vision plug Twixtor handles things like this pretty well for example.

[Steve Bentley]

Also that motion blur looks pretty steppy – go look at one frame. Its pretty hard to motion blur after the fact because you would have to blur each object separately because they are moving radially out from the camera center and rotationally and laterally as the camera weaves around. A radial blur set to zoom would get you closer.

But as Mark pointed out, Twixtor or RealSmartMotion blur can figure out every object’s own blur because it compares frames pixel by pixel. And this scene is the perfect use: Twixter and RSMB have trouble with objects suddenly coming into frame since there is no “before” frame for that object to compare things to. But this shot has everything in frame to start and it all leaves frame eventually.

If you did this for real with a 180 degree shutter, things would be really really really blurry at the edges (think: unidentifiable smeared objects as a still) and less so at the center. So a global blur doesn’t always work.

When we do this for “The Flash” we also add little trailers at pointy edges and streak those points a little longer You can either make a mask or just let a crushed luma key pull out some details that you streak longer than the radial blur for the whole scene. (if that’s what you’re going for). It really adds a sense of speed and covers other sins.

[Ryan Elder]

Oh I was cutting out frames and then adding motion blur to the frames that were left.

[Steve Bentley]

I always pull out a frame of 70mm film from the Imax film Catch the Sun when I’m trying to explain this to the guys here. If you see a bunch of these frames in order you know you are on a roller coaster. But as a single frame held up to the light, its just a blurry mess and you have no idea what you are looking at. Don’t underestimate just how blurry it’s gotta be.

[Ryan Elder]

Okay thanks, but what does the blurriness have to do with it?

[Ryan Elder]

As for adding blurs, I didn’t add a ‘global blur’, I used the Timewarp plug in After Effects as tutorials were telling me to, to create motion blur, but is Timewarp a bad choice?

[Steve Bentley]

If things are moving really fast the camera’s shutter isn’t fast enough to freeze them and make them sharp in a single frame. So things that move fast end up being blurred. In your scene everything is in a sense moving fast relative to the camera because the camera is moving fast (or would have been if you could have shot the push in fast enough).
The reason your version doesn’t look sped up is because the blur/smear level doesn’t match the perceived speed.

[Ryan Elder]

Oh should I have acceleration and deceleration? What if I don’t want that and want a straight speed in the move? But I guess that acceleration and deceleration would help sell the realism?

[Steve Bentley]

I missed this middle post about time warp. Did you use “by frame” or “by pixel motion”? What did you set the shutter angle to and how many samples? I’ve never actually used Timewarp to speed things up, usually we’re using it to make up frames that never existed – when a clip needs to run longer (which it can do brilliantly).
So the motion blur in the plug in might do a good job if you set the method to “pixel motion” and cheat with the blur. Because its a digital shutter in the plug in you aren’t limited to a max 360 degree opening (in other words no shutter). So you can crank that value up to crazy numbers to increase the blur. But you might hit a limit as you will need more samples to make a large shutter angle work, and you may need more samples than there are frames in your clip. Watch the luminence too. It may increase from a too wide shutter angle. Use “Correct for luma changes” if it does.