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Author
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Topic: Novice seeks scope/flat lens advice
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Don E. Nelson
Expert Film Handler
Posts: 138
From: Brentwood, CA, USA
Registered: Nov 2001
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posted 11-26-2001 02:14 PM
With the 35mm projectors I recently purchased(Universal Projector Co.)I received 2 ea. Schneider-Kreuznach Lens's with these specs engraved on the barrel.Cinelux Anamorphic 2x
Ultra MC 2.1/140mm-5.51in. Film 35/70mm
23ft to 500 ft.
Serial no's 14019468 & 480 They are approx 12" long and gold in color.
My Questions: This is a scope lens, can it be made into a flat lens, or do I purchase a completely separate flat lens? (It also came with others lens, Isco-Gottingen, with smaller dia front lens and a large barrel dia. that could screw onto another lens) These lens appear to be in excellent condition, how would I appraise their approx. worth?
thanks.
Thanks
don
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John Walsh
Film God
Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999
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posted 11-26-2001 06:59 PM
It seems like you really have two lens sets. The "Cinelux Anamorphic 2x" is the anamorphic adapter ..... it is screwed to the front of a regular lens, the; "Ultra MC 2.1/140mm-5.51in. Film 35/70mm."The "23ft to 500 ft." is a setting on the anamorphic adapter; you rotate the setting to match the distance from the lens to the screen to correct for astigmatism. The "Film 35/70mm" means the lens will work with 70mm wide film. The "Ultra MC" is the lens model; the "2.1" is the speed of the lens (the ablity of the lens to pass light.) The "140mm-5.51in." denotes the lens focal length (in metric and in inches) .... by putting this number into a formula, along with the image size you want to show (flat or scope), you can figure out the size of the picture at the screen. You probably want to keep the anamorphic adapter... unscrew it and sell off the Ultra MC's if they do not fit your screen. What you do is find out what size screen you will have for flat and scope... a calculation is made to figure out what focal length lenses you want. You use one lens for flat, but to show scope, you buy a "prime" lens to match you screen size and then screw an anamorphic adapter to the front of it. They are good lenses; the two Cinelux anamorphics (new) are about $1000 each; the Ultra MC 2.1/140mm are about $800 each. Whith many theaters going out of business, the market is a bit depressed now. Others would know better than I, but a price guess is about half of new. You can not change the scope lens into a flat, or change their "magnification" characteristics.
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Dave Macaulay
Film God
Posts: 2321
From: Toronto, Canada
Registered: Apr 2001
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posted 11-27-2001 08:51 AM
The 5.51" lens is the actual projection lens, the other one is the cinemascope adapter. The adapter should screw on the front of the main lens.
5.51" is a pretty long lens, if it was used for flat it was probably in an old "shoe-box" cinema with a long throw and a smallish screen.
The 2X adapter means it makes the picture twice as wide - the height remains the same. With side movable masking the same main lens was probably used for both, you can find projectors with swing-out anamorphic holders so you just swing it in front of the main lens for scope. This makes the flat picture kinda small, and only works for 1.33:1 flat images which are unheard of today. With the now normal 1.85 pix (ok, but this is Canada and 1:66 is rare and usually just shown 1:85 here) you need 2 main lenses to get any picture dimension to match in scope v.s. flat... and full top, bottom, and side movable masking is super rare now!Current practice uses top/bottom (usually just top...) movable masking and makes the flat picture bigger than scope so the different main lenses are used. Most new installs are using reverse (shrink the height by 1/2) anamorphics because with the short throws and big screens nowadays a magnifying anamorphic is impractical - they vignette. The distance setting is because of the different magnifications in scope, and horizontal focus becomes different than vertical focus. Setting it to your throw distance is a rough setup. This can actually be totally wrong because if the lens is dismantled by the big front ring being screwed right off - well, that ring is on multi-start threads and only one of the 2, 3, or 4 ways to put it back on will have the distance markings correct. The right way to set it up is with RP40 or another loop with sharp vertical and horizontal lines, and turn it until both vertical and horizontal can be focused at the same time.
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