Well I would normally say, no matter what your destination, that you should shoot in the highest resolution possible… even if it’s “just” for the web. In your case, that would be one of the 1080 formats, not 720.
And… since computer screens aren’t interlaced, you should shoot in one of the progressive formats, not one of the interlaced.
So that leaves you with 30p or 24p. That is just a matter of aesthetics and personal taste/preference. The 24p will give you a more filmic/dramatic look… if you are doing something that would benefit from a cinematic feel, that’s probably your best choice. If you want something more live, “instant,” and video-y looking, then choose 30p (although it still won’t look as video-y as 60i, but remember computer screens won’t display interlaced fields so that’s a moot point).
You are correct in that 60fps is a good start for slow motion. BUT… that’s 60fps… 60 frames per second. A 60i setting does not give you 60 frames per second, it’s still just 30 frames per second (it’s 60 fields per second, each frame made up of two fields). Now you can do that if you have the ability (and proper editing hardware/software) to separate each field and turn them into frames… but you lose half of your resolution, of course. I don’t know if your camera will actually shoot a true 60 frames per second… but if it will, yep, that’s what you’d want for slow-mo.
As for not being sure when you want to slow-mo… it’s still doable, but not ideal. It’s much better if you know which shots you want to slow-mo before you shoot them, because you’ll want to change your shutter speed. “Regular” speed footage is usually shot with a “normal” shutter which is one over twice the frame rate (so 24p footage would have a 1/48th shutter, and 30p footage would have a 1/60th shutter). If you slow down that footage you will have too much motion blur in each frame for a good looking, convincing, and smooth slow-mo shot. So, if you know a shot is going to be slowed later, you should shoot it with a much higher shutter speed… something in the 1/120th to 1/160th neighborhood…. depending on how much you want to slow it. And one of the keys is to remember to change your shutter speed back to a more normal setting when you resume normal-speed footage… which is easy to forget to do, and you wind up with too-crisp and stuttery-looking footage.
T2
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Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com
