A while back I had seen a video on youtube which used a fascinating editing technique to visualize the flight paths of birds as they rode the airwaves in the sky.
I was really amazed at how this technique brought out the inherent patterns in nature that always surround us, yet we are rarely cognizant of. About a year went by during which I became much more proficient with my camera and editing techniques, and I somehow came across the video again. I had, and still have very little experience with video editing software aside from timelapse editing, and figured this was something that was way out of my league. Nevertheless I decided to post a request for the technique to the author on youtube who goes by poochengeez, who has a great variety of interesting videos with unique editing ideas. To my surprise he responded and the explanation was a lot easier than I had anticipated. Since I figure their may be interest among people online on how to do this, I have decided to post this quick tutorial using Adobe After Effects CS4. This is actually quite easy. With a few clicks, and some waiting for rendering time you can get effects like this!
Firstly you will need a video file of birds in flight. A wider angle and good foreground will help to give this technique more impact and sense of scale. The video should also be at least a minute long, so as to give enough time for the effect to fully take hold. I chose a video of a vulture circling on thermals for this example which really emphasises the “echo effect” that we achieve with this technique.
Open the file in Aftereffects.
In Aftereffects, in order to work on a file we need to move it down to the workspace on the bottom left. Drag it from the top left to the highlighted space bottom left.
Now we’ll go to the effects menu and select time>echo
This will apply the time echo effect to the sequence. We have the options for the effect at the top left. We need to configure the effect to make it work with our footage. The first step is to select echo operator>minimum This means the entire frames will not overlap and create far too much exposure and just turn white, instead it will only overlap moving subjects, like our bird.
Next we need to decide how long the interval or “echo” will be between our subjects. This will be completely dependent upon your particular footage. Enter a time in seconds into the Echo Time section. I have chosen .25 seconds which works well for this sequence, but you will need to experiment.
Next we will need to decide how many “echoes” of the subject we want. Keep in mind that while more “echoes” look great, it is EXTREMELY memory intensive, and the higher you go, the longer your computer will likely be unusable due to Aftereffects using all your RAM. So enter an integer into the Number of echoes section. I have chosen 100, and don’t like going higher than that, as this 1 and a half minute clip took over 7 hours to render!
Once these values have been set, you can preview how the sequence will look. Don’t try actual playing it in the preview as it will likely be too slow, just choose a frame in the middle to see how it looks. If you are not happy go back and experiment with the echo time and number of echoes values until you are happy.
Once you are happy, go to composition>add to render queue
This will bring your video into the rendering area on the bottom. When you are ready to sacrifice your computer for a while, go ahead and hit Render!
Please leave a comment if you found this tutorial helpful! This is the first one I have created and am interested in doing more if I get positive feedback!