Looking for help with Echo

[satisfied_soul1334]

I do night photography and will often move lights through the images, creating light trails during long exposures.  I recently set up a video camera right above my still camera to capture a video, the intent being to use Echo and show on video how a light trail is built.

So I set up Echo and put it on Maximum for blending, the issue is that there are gaps in the echo effect.  I've shortened the time I feel like I have adjusted nearly everything but am still frustrated at the gaps I continue to see.  Is there some obvious thing I am doing wrong here or another effect I should be using instead?

[Kyle Hamrick]

You should be able to get Echo down to a smooth/continuous line by setting the Echo Time low enough and Number of Echoes high enough. 

I'd recommend starting by setting Echo Time to 1/ your comp's frame rate. (So if you're working at 24fps, type in 1/24 - and don't forget to set this to a negative value, or else it will be in front of your footage). Start dividing this number by 2 and increasing the Number of Echos. You should get there eventually!

In this example, the Echo Time is actually set at -0.0016.
(The red square is a second layer, created for visibility of this object in the current frame.) 

You may also want to experiment with having a higher frame rate on your source footage (if possible), as that will require fewer echoes to be created for a smooth trail. 

[satisfied_soul1334]

Thanks.  I think Echo is just better suited for animations instead of footage.  Here's a time of -0.001 with a number of 900.  The framerate was set to 30 fps.

[Kyle Hamrick]

I do agree that graphics will fare better, because AE has the info to create all the frames for us.
If you have the ability to get a higher frame rate at capture, I think you'll have better luck filling in the gaps. You're essentially looking for more of a frame-blending situation here, because the frames we're calling to don't actually exist. 

[Kyle Hamrick]

You might explore the effects CC Force Motion Blur or Pixel Motion Blur, and see if either of those is able to fill in those gaps?