posted 12-24-2008 04:27 AM                    

quote: Steve Guttag

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Steve go to Schneider's web site and download their Theatre Design Pro (there may be a version here too).

That will help you see just what point of acceptable throw vs. screen size occurs.

I think you are mis-reading your lens selector...a 25' wide picture at 20-feet needs about a 33mm prime lens. Doing the math:

((2x.825)/25) x 20 x 25.4 = 33.5mm. You didn't multiply the width of the aperture by 2 in order to allow for the 2x anamorphic. So, using 50mm as the bare minimum of a known workable, non-special order lens with a 25' wide screen.

Rework the equation so that it looks like (50x25)/(25.4x2x.825) you get you required throw to be 29.83' or about 29'-10"...probably something you can do. It will still suck putting a 50mm integrated anamorphic in the Super (it will be way back in the machine and you won't be able to use a stop ring) but it will likely work.

Steve

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Thanks for the link there Steve-o, This thing's kind like a projection slide rule so no doubt I was reading it incorrectly. I appreciate the cinema math lesson and will attempt to use it, though with the link, it may not be neceassary but it's still nice to know how to figure it out in case I'm ever asked.

quote:

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I got this scope lens from a cinema equipment dealer here in San Francisco
that I use on my Simplex XL at a short throw of abt 25-30ft & it works great.
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Last year I loaned it to a well known San Francisco theater that used it for several months after their scope lens was damaged.

The throw there was just over 100ft, and they claimed the picture looked better than their regular scope lens.
The theater even offered to buy it from me. I refused to sell.

I don't have an optical bench or a lens resolution test film (Do they they still make those things? - haven't seen one in years!)so I don't have a quantative way of measuring or comparing it to other lenses.

The lens is marked: H. Chretien Hypergonar, HI-FI-2, Societe Technique Optique De Precision

Distances from "7 - 50" are scribed on the adjustment collar. I'm going to assume these distances are in meters since the lens was made in france. There is also an "infinity' setting.

Labels on the box it came in when I bought it indicate it was originally sold to the "UA Arden-Fair" in Sacramento, CA.

This lens works so well for me, that I recently found and bought a 2nd one.

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Jim, I'll definately keep an eye out for this lens. It looks to be French (I did a Google so I THINK that's were it was made). It may be just what I need. Are you sure it will work with the Sper though? I THOUGHT the XL was a little different but maybe I'm wrong.

posted 12-27-2008 01:40 PM                    

quote: Jim Cassedy

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they claimed the picture looked better than their regular scope lens.
The theater even offered to buy it from me. I refused to sell.

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