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Topic: Question regarding light output

John Pytlak
Film God

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

posted 05-15-2000 08:29 AM

Mitch:

As you know, SMPTE Standard 196M specifies 16 footlamberts as the aim, and allows a range of 12 to 22 footlamberts. So having a bit too much light won't really hurt, and for most pictures, may actually look better! Going above 22 footlamberts with a two-blade shutter makes flicker more noticable.

You can always defocus the lamp somewhat to get less light output and better uniformity. You could also "cash in" the excess light and use a three-blade shutter to reduce flicker.

Generally, "Brighter is Better":
http://www.kodak.com/US/en/motion/newsletters/reel/spring98/pointers.shtml

------------------
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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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 05-15-2000 12:19 PM

Continuing along the lines that John suggests, in addition to a 3-bladed shutter, you would do good to look for slower lenses (i.e., numerically higher than f/2.0, like f/2.5, f/3, etc...). You'll lose all kinds of light, and get fantastic depth of field, too.

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Better Projection Pays!

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John Pytlak
Film God

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

posted 05-15-2000 12:59 PM

Tim: AFAIK, the IscoOptic "Ultra-Star HD Studio" lenses are selected stopped-down versions of their standard lenses, trading some light efficiency for greatly improved optical quality. Great choice for smaller screens, where getting enough light is easy to do.

My "ultimate" small-to-mid size screen theatre would use a three-blade shutter (to get rid of flicker), Isco Ultra-Star Studio HD lenses, and run at 22 footlamberts.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-15-2000 03:34 PM

I'd rather defocus the bulb, reduce the current or even put a ND filter inline before adding a 3 bladed shutter. Reducing the flicker takes a little bit of that film look away.

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Pat Moore
Master Film Handler

Posts: 363

Registered: Mar 2000

posted 05-15-2000 07:08 PM

I'll side with John on this one. I think the 3-blade shutter adds a bit to the "look" of film. 72 images per second looks a lot nicer than 48, and you can run some higher light levels and look great. Problem is they are light hungry -- you need more horsepower to make it happen. Shouldn't be too much trouble in this application, though.
Good luck!

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Josh Jones
Redhat

Posts: 1207
From: Plano, TX
Registered: Apr 2000

posted 05-15-2000 08:26 PM

I hate to get off the subject but how good are those tawakia machines? a guy in minneapolis wants to sell me his TSR for 500 bucks. Is it worth it?

Josh

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Michael Barry
Jedi Master Film Handler

Posts: 584
From: Sydney, NSW, Australia
Registered: Nov 1999

posted 05-15-2000 11:21 PM

I've used Tokiwas. I would suggest an alternative even if space or portability is at a premium since they're not necessarily more compact than other models and they're just as heavy.

They run quite noisily, too, and aren't that gentle on film. For what they are, they're not all that bad, but you could do much, much better.

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Christopher Seo
Jedi Master Film Handler

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

posted 05-16-2000 02:15 AM

Regarding the triple-bladed shutters: I can understand what that would be for single shutters, but is there such a thing as a triple-bladed double counter-rotating shutter such as would fit the Century JJ or DA? That sounds like it would be pretty rare and exotic at best.

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