Blaise Douros
Forum Replies Created
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There are two kinds of flicker; the natural kind that results from using 24p, and the kind that results from shooting under fluorescent, HMI, or some kinds of LED lighting.
24p became the standard framerate because it was about the minimum needed for humans to resolve motion (less fps means less film used), and because it was easier to sync audio to in the film days. In theory, there’s no reason we should prefer 24fps over 30, 48, or 60fps…except that we’ve conditioned to see that kind of flickering, slightly stuttered motion as filmic, and faster framerates as “home-video-y.” It’s an emotional thing, and helps with the suspension of disbelief.
As for the lighting question; fluorescent (and some other) types of lighting flicker on and off at a rate of 60 hz because that’s the frequency at which our electrical grid functions. If you have a FASTER shutter speed than that, you will start to see lines rolling down your footage as your camera sees the periods of time that the lights are off. So shooting at certain shutter speeds will make sure that you don’t see these rolling lines in your footage. This may help you understand: https://www.red.com/learn/red-101/flicker-free-video-tutorial
Now–if you shoot under tungsten lighting (i.e. regular halogen bulbs), this is not a problem. It’s only lighting types that are regulated by the frequency of the electrical grid.
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1) Only you can answer what looks acceptable to you. However, the key is knowing what kind of effect you’re looking for. The faster you speed up your shutter speed, the closer you’ll get to the look in the Gladiator fight scenes.
2) I’d stick with 1/125, if you’re looking to show smooth, crisp motion at 60p. 1/60 will still show roughly the same amount of motion blur as when you use 1/50 with 24p footage.
3) You can’t use a 1/48 shutter at 60p–because you’re shooting at 60 fps (1/60 of a second for each frame), the maximum amount of time that the shutter can be open is 1/60.
3.5) Some higher end professional cameras actually CAN have the shutter open longer, but it will create this timelapse-y motion trail effect that is only really useful for special effects. Most cameras will not allow you to set the shutter speed lower than the frame rate. You can create a really neat, dreamy look by setting the shutter speed at something like 1/4 with the frame rate at 24p. But it’s not useful other than as a special effect.
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You could always use a manually keyframed Skew transformation to offset whatever the rolling shutter repair tools don’t.
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Can you post example footage? We can help you better if we can see what some of the problems are.
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The subject’s clothing, skin, hair, etc…all will have rough edges, likely difficult to remove the green contamination from. 24 mbps or not, the footage will still be AVCHD, which is a 4:2:0 color space, and makes keying extremely difficult. It’s not impossible, but you are setting yourself up for a rough time, especially if you’re not experienced at compositing.
The reasons why this is the case are too complex for me to write down here–do some googling on 4:2:0 vs 4:2:2 for chroma keying, and you’ll see what I mean. You will save yourself major headaches in post if you can rent something with a 4:2:2 codec for this shoot.
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Is there any reason you want to do this in After Effects, and not Premiere? I ask because Dynamic Link is an absolute dog for performance, and you do NOT want to run four streams of DL footage out of AE.
You could achieve the exact same thing in Premiere by creating a sequence for each camera, overlaying a title on your footage in that sequence, and then importing that sequence as a clip into your main edit timeline. No After Effects, no Dynamic Link, no trouble. Your performance will be a hell of a lot better, and it will be easier.
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I’m not sure how to answer this question, except to tell you to think about it a little. You have a screen that is 10 feet wide. An HD picture has an aspect ratio of 16×9, or a 1.77:1 ratio. That means that, if we do the math, the maximum height possible for your subject is 5.65 feet tall, or roughly 5’7″. That doesn’t account for any movement of the edges of the greenscreen, nor does it account for the size offset from the subject to the screen. So yes, it is absolutely a physical limitation.
The real answer to your question, though, is that it doesn’t matter if the greenscreen’s edges are visible. Frame your shot to get your actor in the shot, and then when you’re setting up the composite, use a junk matte to get rid of the sides of the picture.
Shooting greenscreen with the Canon HF M41 will give you a VERY hard time because it shoots with a highly compressed codec that records extremely limited color information. You are likely to get very jagged edges when pulling a key. So be prepared for that.
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After effects is not the right venue for this. If you’re really serious about doing this, you’ll need to hire a 3D artist to create a model that you can composite on. Hair simulation and replacement is just not something that AE is remotely capable of. Once you have a 3D modeled haircut that’s animated to match the movements of the gal’s head, you can then use AE to track and composite the new hair onto your actor.
If you came here looking to learn anything at all, learn this: it is way easier to get it right on set than to fix it in post!
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My company owns the FS7, and I work with it several times a week, both shooting and editing. It can apply LUTs selectively to different monitor outputs; but if you apply the LUT to the SDI-1 output, it will also bake it to the footage. This is pretty clearly labelled in the menu, so it sounds like this AC was not really paying attention. Not that I’m blaming and shaming, since I have done the same thing. My guess is that they were trying to get the waveform to display in the monitor, which it won’t unless you apply the LUT to all outputs.
Regardless, I think you’ll find that the footage is still eminently gradeable. At Rec709, it is still retaining a lot of usable color data at 10-bit 4:2:2. Good luck!
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It depends on the LUT used to bake into the footage. If the LUT isn’t actually throwing away data by dropping the highlights and black clipping levels, they might have a fighting chance. But since what a LUT does in the first place is re-interpret the video color and luma data to be spread across a different curve, it stands to reason that you should be able to apply an inverse curve to re-distribute the data back to its original level, so long as none has been lost in the process.