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Topic: Prismatic projectors?

Christopher Seo
Jedi Master Film Handler

Posts: 530
From: Los Angeles, CA
Registered: Jun 99

posted 06-16-1999 03:20 PM

Scott Norwood's post in the "Austin Powers stolen" thread reminded me to ask why we haven't seen similar advances in projection. I read that one "Hollogon Rotary projection system" was developed using exactly this 24-sided prism. It seems the benefits are enormous--less wear and tear for both the print and projector, flicker-free image, etc.

Incidentally, I have always wondered what causes the "ghosting" whenever we watch a shot that pans; the image moves in a jerky manner and seems to vibrate. Would this problem be improved with higher rates of frames per second, or would this new projector eliminate that?

And why doesn't anyone use this projector?

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 06-16-1999 07:22 PM

Why use a good projector when you can just buy the Christie package for cheap cheap cheap?

All kidding aside, the the motion artifacts that you see when a camera pans slowly would probably be improved only slightly, as the projector is still running at 24 frames per second. Even at 30 frames per second there will still be some of this going on. I would love to try out t a projector with that technology, if the rest of it was designed equally as well. Who cares if you don't have any flicker if your image is shaking around all over the place, y'know?

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 06-01-2000 02:28 PM

Actually I was reading through one of my old books and there was a system called the Machau Arcadia projector built by Lietz in the early 1900's
Perfectone and Sondor both build units on this principle for studio aplications

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 06-01-2000 02:40 PM

Prism systems have been used for editing tables and inspection projectors (e.g., at the tail end of lab processing machines), but never were commercialized for large screen applications. I suspect contrast, steadiness and heat-handing ability would be challenging to this technology.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 06-01-2000 02:47 PM

Apparently the only problem the arcadia had was its size (the fact that the film twisted to go hoizontally through the prism and used a perescope projection to the objective lens)
and that a soundhead was difficult to mount to the beast
But they were noted for being very stable units

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 06-01-2000 03:30 PM

I'm pretty sure that Arriflex (the camera company) makes one of these for rear-projection applications. At least, I vaguely remember seeing a picture of it.

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