you can do slow-motion by shooting at a high frame rate and then lower the playback frame rate
you could, for example shoot 60fps, then take that clip into ae, right-click the clip in the project window, choose interpret footage>main, and set the frame rate to 24fps.
if you drop that clip into a new comp, it will play back in slow motion (40% of the original speed).
some cameras can shoot much higher than 60fps, so you can achieve even slower motion.
ae can also interpolate new frames in between recorded frames to make things slow-mo too. if you were to take a clip and drop it into a camp, then set the stretch property to 200% (if you don’t see the stretch property, right-click in the time line where it says ‘layer name’ and then choose columns>stretch) and enable frame blending (layer>frame blending>pixel motion), ae will interpolate a new frame in between each existing frame.
it’s not perfect, and there will be artifacts in the image and there are limits to haw far you can push it, but it can be useful.
to ramp speed up and down, rather than using stretch, you could use time remapping. you enable that by selecting the footage layer in the comp and chooseing layer>time>enable time remapping. it will allow you to use keyframes to change the speed. it’s not as intuitive as it could be, so you might want to find a tutorial on using time remapping. and again, pixel motion is what will interpolate the new frames, so that will need to be enabled.
there are also effects that can be use and slowdown and speed up footage and can do a better job of interpolating frames. timewarp is one that comes with ae, and twixtor is a third party option.
using a combination of shooting at as high of a speed as possible (like 60) then adjusting the playback speed to 24fps, and using ae or a plugin to interpolate new frames will give you the best shot at getting good results without a more expensive camera.
Kevin Camp
Art Director
KCPQ, KZJO & KRCW