Motion tracking & Motion blur problem, oh no!

[Lou Cannizzo]

Well, like I said, “it’s like the tracking is off by 1 frame”
I didn’t say it was off by 1 frame. That quick fix I would have done.
I think it must have to do with the shutter. Anyway, I think I found the solution, you were close, I had to Precomp the tracking layer and then motion blur the precomp.

Thanks again,
Lou

[Darby Edelen]

My guess is that you need to adjust the phase of your shutter. Different settings for the phase can cause motion blurred layers to appear to shift in space. I’ve attached an animated GIF example of this. These images are all taken from the same frame of animation, the only thing that I changed was the shutter phase.

Darby Edelen

[Todd Kopriva]

I think that Darby is spot-on.

Here’s an excerpt from the “Motion blur” section of After Effects Help:

“A Shutter Phase value that is -1/2 of the Shutter Angle value is best for a layer that is composited on top of another using motion tracking data. (For example, Shutter Phase = -90, Shutter Angle = 180.) This setting combination causes a blur that is centered on the original object.”

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Todd Kopriva, Adobe Systems Incorporated
putting the ‘T’ back in ‘RTFM’ : After Effects Help on the Web
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[Lou Cannizzo]

Thanks guys for all your input.
The one thing I don’t understand is, If the shutter phase causes the image to “shift” in time, how come when I try to re align the image back to it’s original spot, it still drifts all over?

Anyway, I will try what you said to do..
Thanks,
Lou

[Stuart Elith]

Your track will affect this as well – when you say the track is ‘spot on’ it’s actually hard to know, because the motion blur affects the position of the object, technically since it’s blurred the object seems to be in multiple places at once.

I have found that sometimes i’ll do a tricky track, and part way through correct the tracker to align with what i think should be the correct spot in a blurry frame, but that later this messes it up when the blur is applied. So once you get the plate to fit overall (by playing with the shutter controls as explained above), you may need to readdress specific parts of your track.

[Megan Bagshaw]

Hey, I have been getting the same problem with motion blur, so I used this guys tutorial. He created his own motion blur using the directional blur effect and a quick little expression. It’s working rather well for me, just had to bump the .transform.position.speed/20 to about .transform.position.speed/1500.

I’m sure there’s a better way out there somewhere though haha.

https://www.youtube.com/watch?v=EpAvFeV4Lak