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how to capture at 59.97 for slow motion using dvx100a
Posted by bigcurt2000
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Re: how to capture at 59.97 for slow motion using dvx100a February 12, 2009 09:51AM |
As far as I know, the only correct way to faux-overcrank 60i to 24p is with After Effects. If you tell After Effects to interpret your 60i footage as separate fields, it will do the Right Thing? when you retime it by 250%, separating out each field of 60i and interpolating it up to a whole frame of 24p. This throws away half your vertical resolution, obviously, producing a slightly soft end product, but it works remarkably well for what it is.
In fact, I recently did a project where I took 60i footage (B-roll of Grant Park shot on election night) and retimed it to 24p using this technique, then rendered it out of After Effects with pulldown to cut it into a show that was otherwise all 60i. It worked very, very well. Better results than optical flow, and much faster.
But yes, it is a little bit of a pain, workflow-wise.
(I still haven't the foggiest idea why anyone would ever shoot 30p.)
In fact, I recently did a project where I took 60i footage (B-roll of Grant Park shot on election night) and retimed it to 24p using this technique, then rendered it out of After Effects with pulldown to cut it into a show that was otherwise all 60i. It worked very, very well. Better results than optical flow, and much faster.
But yes, it is a little bit of a pain, workflow-wise.
(I still haven't the foggiest idea why anyone would ever shoot 30p.)
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Re: how to capture at 59.97 for slow motion using dvx100a February 12, 2009 11:06AM |
I've tried that, Noah, but FCP doesn't do it right, at least in my experience. It frame-blends, which produced really ugly results for me. Maybe I did it wrong.
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Re: how to capture at 59.97 for slow motion using dvx100a February 12, 2009 11:25AM |
My problem with 30p is actually old news; I've gone into it at length in other threads here. But in short, it's this: 60i is the format for live TV, news and sports. That's what people are used to seeing. On the other hand, 24p is the format for scripted television and film. Again, that's what people are used to seeing. Shooting 30p gives you a motion quality that's unlike either; it doesn't have the immediacy of live television, but it doesn't have the right cadence or motion blur to be dramatic either. It ends up just looking wrong, like cheap home video.
More than anything, it's a factor of the shutter angle. For moving pictures, your shutter should always be 180°, unless you're making a specific artistic choice (see the Normandy Beach sequence in "Saving Private Ryan," for example). At 24p, your shutter is open for 1/48th of a second, which yields a very specific motion blur quality. At 60i, the shutter ? to the extent that video cameras can be said to have a shutter ? is open for 1/120th of a second, which gives very little motion blur, which defines that "live" look. But at 30p, your shutter is open for 1/60th of a second, which yields perceptible motion blur, but still less motion blur than 24p, which gives your footage a stuttery, jittery look.
The alternative is to open your shutter all the way up, to 1/30th of a second, which is something electronic cameras can do that film cameras can't. But that's too much motion blur, creating a streaky, afterimage-y look that the audience associates with home movies.
And of course, if you set your shutter to 90° at 30p, you get the 1/120th exposure of 60i, but at half the frame rate, which just makes everything look stroboscopic. Again, there might be artistic reasons to do that on purpose ? "artistic reasons" is a valid excuse for anything, eventually ? but your footage won't ever look right.
I guess it really boils down to a matter of preference. I don't like the 30p look, myself. But more than that, I've never had a client ask for that look. To the contrary, whenever the option has come up, I've never heard anybody in the industry say they like, or even tolerate, that look. And when I did some camera tests a few years back just to see what this whole "30p" thing was about, nobody who saw the footage reacted positively to it. Responses ranged from "it looks cheap" to "something's off but I can't put my finger on it."
Sorry for the derail. We now return you to our thread already in progress.
More than anything, it's a factor of the shutter angle. For moving pictures, your shutter should always be 180°, unless you're making a specific artistic choice (see the Normandy Beach sequence in "Saving Private Ryan," for example). At 24p, your shutter is open for 1/48th of a second, which yields a very specific motion blur quality. At 60i, the shutter ? to the extent that video cameras can be said to have a shutter ? is open for 1/120th of a second, which gives very little motion blur, which defines that "live" look. But at 30p, your shutter is open for 1/60th of a second, which yields perceptible motion blur, but still less motion blur than 24p, which gives your footage a stuttery, jittery look.
The alternative is to open your shutter all the way up, to 1/30th of a second, which is something electronic cameras can do that film cameras can't. But that's too much motion blur, creating a streaky, afterimage-y look that the audience associates with home movies.
And of course, if you set your shutter to 90° at 30p, you get the 1/120th exposure of 60i, but at half the frame rate, which just makes everything look stroboscopic. Again, there might be artistic reasons to do that on purpose ? "artistic reasons" is a valid excuse for anything, eventually ? but your footage won't ever look right.
I guess it really boils down to a matter of preference. I don't like the 30p look, myself. But more than that, I've never had a client ask for that look. To the contrary, whenever the option has come up, I've never heard anybody in the industry say they like, or even tolerate, that look. And when I did some camera tests a few years back just to see what this whole "30p" thing was about, nobody who saw the footage reacted positively to it. Responses ranged from "it looks cheap" to "something's off but I can't put my finger on it."
Sorry for the derail. We now return you to our thread already in progress.
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