View Full Version : camera exposure time ?

09 September 2004, 12:37 PM
Hi !
I need to recreate the effect of a light moving in front of a camera in the night in order to see light trails.
I've tried motion blur but it doesn't do the trick because it blurs objects in time frames before and frames after.
I think I can't do that whithout any plugin but I'm don't think some kind of plugin exists.
I also tried in after effects but didn't manage to get a satisfying result.

Any idea please ?

09 September 2004, 01:52 PM
Maybe you should think to add it in post by using this plugin for motion blur. I think you'll get the effect you want if you push the value of the blur in AfterFX or C*

09 September 2004, 02:11 PM
arse. Just spent a few mins typing something out and the server went down so I've lost it all.

anyway -

you could create some duplicates of the lights, offset their keyframes by a few frames each (light2 starts at keyfrm4, light3 starts at keyfrm8, etc..). Edit their intensities a little bit and make them selective so they light nowt up and therefore dont affect your scene. Just thinkin on me feet here but if your using some effect on the light - the bleaching might just cause them to work well together?

render off just the light but in yer render globals, set the startframe and endframe, but edit the 'by frame' to 0.1 so you get ten frames rendered for every normal frame of your beauty pass. take this into afx, layer it over and use the 'echo' command. Because theres more frames you should get a much more subtle blurring of the light. Bit of glow, adding, bleaching etc and it could look quite nice?

just some thoughts. Wonder if either works.. :shrug:


09 September 2004, 02:33 PM
I've already tried reelsmart motion blur but the result is not reallistic and kind of weird.

anthonymcgrath I'll try what you proposed.

Thanks guyz !

09 September 2004, 02:41 PM
let us know how it gets on and what method you use seb4d - I were only thinkin on me feet there but I reckon with a bit of tweekin you could get some nice results from it. Post a pic if you get a mo :D

09 September 2004, 06:45 PM
Ok finally my friend used reelsmart motion blur and echo and he managed to get a satisfying result.
Thanks again for your help !!

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