Carlos E. R. wrote:
The Tuesday 2006-10-31 at 17:28 +0100, Matthias Hopf wrote:
Well, I think I remember that I read that long ago as well, but later on I read that the typical shutter discs rotate three times as fast as the film moves nowadays. I guess they couldn't make the film transport mechanism fast enough back then. Today they are using low air pressure devices to suck the individual frames into place... :-P
Low air... whatever? I'm outdated. Sigh.
Yes, I saw the air pressure thing on the Science channel. It is what has eliminated most of the vertical scratches form the theater experience.(I feel outdated all the time, dealing with computer technology)
Yes, the 35 mm machines I handled used a shutter disk or cylinder, blocking the light source two times per frame. But in order to do that they have to compensate the dark periods with higher brightness, ie, stronger light source... The machine I used had an 2 KW arc lamp (around 65 Amps), and that's pretty hot: if the film stops it burns within seconds. So they invented xenon arc lamps. They are relatively colder, brighter, and much easier to use (the traditional arc lamp uses carbon composites electrodes that get burnt and have to be continuously adjusted to compensate during the session; a faulty machine or human and the spectators get mad). I suspect that only with xenon lamps can the apparent fps be increased.
(http://en.wikipedia.org/wiki/Xenon_arc_lamp, http://en.wikipedia.org/wiki/Carbon_arc_lamp).
I'm surprised that projectors don't use strobes yet to replace the shutter, as with extreme slow motion cameras.
The film movement is a different thing: it moves at 24 fps, not continuously, but intermittently. That's what limits its speed. It moves a frame fast, then it is hold in place for the rest of the 1/24 S left, while it is projected into the screen two or three times.
It is unfortunate that that fps of 24 doesn't match the TV rate of 25 or 30. Computers are different.
And, returning a bit to "topic". I wonder if sometime in the future we will see digital cinema, kind of super-high-definition-dvd. The definition in film is tremendous, more so with the 70mm film; coupled with the brightness and size of the screen is something the digital world can not reach yet, AFAIK.
I think we may see something like this in the future. Perhaps through better optics, or some sort of Laser tech.
So I guess it's save to assume this improved a bit :) 48Hz is barely enough to have a steady image...
The slight headache is part of going to the movies experience :-)
I guess I'm lucky there. I only get headaches on rare occasions from the computer screen, never at movies. -- ED -- p.s. I messed up again, Carlos. Sorry!