8mm Forum: Relative Screen Brightness

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Topic: Relative Screen Brightness

Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted February 23, 2014 02:35 AM

At one time 16mm projector owners were happy with their f/1.9 lenses and their screen brightness, then along came newer projectors with an f/1.6 aperture.

Then came the f/1.4, until today most 16mm projectors have an f/1.2 lens fitted as standard.

As members will know I have recently bought an RCA 1600 and I thought I would share with you some data from its instruction book.

Taking the supplied f/1.6 lens as the reference point of 100% we have the following:-

f/1.4 = 130%
f/1.8 = 79%
f/2.0 = 64%

Obviously this RCA model was introduced before the f1.2 lens became commonplace.

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Maurice

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Paul Mason
Jedi Master Film Handler

Posts: 540
From: Aldershot, Hampshire, UK
Registered: Nov 2013

posted February 24, 2014 03:31 AM

Interesting figures Maurice. The 16mm projector market never produced a wider aperture than F1.2 as far as I know, although an F1.0 or F1.1 might have found buyers. Only the 50mm lenses were available in F1.2 although professional users might have welcomed an F1.2 64mm or 75mm or 100mm while the wide angles were generally limited to F1.4. Bolex produced a F1.3 35mm and a 32-70mm f1.3 zoom was available for Bell & Howell and others.

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Paul.

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