John Galt article question

Al MacLeod

Al MacLeod

Well-known member
Please don't delete this post........

I've just read the Creative Cow article on "the truth about 2k, 4k and the future of pixels" in the pdf downloadable the Cow has made available.
The 24 frame versus higher frame rate discussion mentions two bladed shutters used in 35 motion film cameras.

This would seem to result in the perception of 48 frames per second.

Is there anyone with experience in 35 motion film that is willing to expand on this?

A recent post on a James Cameron article referenced the same two bladed shutter/48 fps phenom.

This seems to put an HD camera shooting at 24 fps at half the frame rate of 35 film cameras....is that the way it works?
 
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I believe two bladed shutters are used in 35mm projection, not capture. This is so the projector shows every frame twice. If it only projected once, the resultant flicker would be very noticeable.
 
Batutta said:
I believe two bladed shutters are used in 35mm projection, not capture. This is so the projector shows every frame twice. If it only projected once, the resultant flicker would be very noticeable.
Click to expand...

My brain picks up speed as the day does on...two bladed shutter, each frame of 24 fps film shown twice...

That leaves hd video at 24 fps (assuming viewing at true 24 fps) with more studder, right?
 
Al MacLeod said:
My brain picks up speed as the day does on...two bladed shutter, each frame of 24 fps film shown twice...

That leaves hd video at 24 fps (assuming viewing at true 24 fps) with more studder, right?
Click to expand...

Not really. If you set your 24p camera with a 24 fps shutter, your video will look very smeary as they mentioned and negate much of the stutter, but it won't look quite like film. That's why people usually set the shutter to 48 and up, as that matches what people are used to, and you'll get the same amount of judder as a film camera gets. If you want to see an example of what 24fps HD set to a 24 shutter looks like, watch the running through the jungle scenes in Apocalypto. You'll see that smeary video look. No video monitor displays true 24 fps. It's usually 60 fps minimum, with frames repeated. Some new HD sets can display at 48fps, which is supposed to be ideal for watching film content as it replicates the two bladed shutter in film projection.
 
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Then all the talk of "true" 24 frames per second is only for folks with film projectors....the hd video crowd is getting at best 3-2 pulldown on video displays and pretending it's 24...
 
Al MacLeod said:
Then all the talk of "true" 24 frames per second is only for folks with film projectors....the hd video crowd is getting at best 3-2 pulldown on video displays and pretending it's 24...
Click to expand...

In a manner of speaking, but it is still captured at 24 frames, which is what really matters, and keep in mind the theater is projecting at 48 fps.
 
I was hoping one of the "24 fps or bust" types would speak up here, but I suppose their silence speaks volumes...
 
Not sure what you're getting at, but if you mean 24p HD isn't really 24p, well...it is, because the recording device is capturing 24 images every 24th of a second, exactly like a film camera. The only difference in HD being that the shutter is capable of being open for the entirety of that 24th of a second, wheras a film camera, because of its mechanical shutter, can only be open for half of that 24th of a second...As the article stated, this is not ideal for capturing movement because of the problems with judder, but its part of what people have come to accept as the film look, which is why many people here pursue it. It gives a film the perception of greater production value. People have experimented with higher frame rate projection before (SHOWSCAN), and the results are supposed to be incredibly immersive and lifelike. At higher speeds film grain cancels itself out and you get a sort of glass window effect. Never caught on because it uses twice s much film, so it's twice as expensive. I think higher frame rates should be used on 3d films, which are much better now but still have problems with blurry smearing on fast action because of motion judder.
 
It's not an argument for or against 24p...it's trying to wade through personal likes, dislikes and opinions presented as fact.
Your posts have been spot on...please don't take offence at what I'm writing. I am trying to reconcile the things I read by folks like Galt and Cameron with what is strongly supported by folks posting on dvxuser in the frame rate arena.
Computers get faster, memory gets bigger and , clock speeds for everything electronic goes up and while having to constantly upgrade is a pain, generally we all see the benefit.
For some reason frame rate is stuck in limbo and for the life of me I can't see any good reason for it. As I've said before I'm a simple man with simple ways and I can't shake the feeling I'm missing something.
It's a mystery to me and I suppose one should have some of those...keeps you on your toes !
 
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