Film-Tech Forum ARCHIVE: CinemaScope Lense

This is topic CinemaScope Lense in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Al Chaney (Member # 794) on 02-18-2003, 06:34 PM:

I would like to add a Cinemascope lens to my Century C projector.
My prime lense is a Wollensak 2 3/4" f/1.9 Cinema Raptar projector lens. My screen is 16ft. wide and my throw distance is 40ft. Can someone tell me which cimemascope lens can I use, where can I find one, and what can I expect to pay?

Al

Posted by Pat Moore (Member # 380) on 02-18-2003, 06:45 PM:

Al; assuming that 2-3/4" is your flat lens, that matches with the diemnsions you gave with a picture height of something like 6-1/2 feet with a 12ft wide picture. The scope lens focal length should be around 105mm -- between 4 and 4-1/4". That will fill a 6.5 x 16 screen with minimal cropping.

Pat

Posted by Steve Kraus (Member # 476) on 02-18-2003, 07:40 PM:

Expect to pay from $100-150 for an old no brand lens to perhaps $1500 for the finest new anamorphic. Naturally if you go the latter route you're not going to want to attach such a top quality lens to the prime lens you describe or others of that caliber.

Posted by Greg Mueller (Member # 17) on 02-19-2003, 10:31 AM:

If you go to Schneider's page
http://www.schneideroptics.com/software/
and download the theater design software you can figure out all sorts of neat stuff. And... it's free!

Posted by Dave Macaulay (Member # 813) on 02-20-2003, 08:11 AM:

You have several choices...
Judging from your prime lens, you aren't going to buy a new integrated anamorphic as this would be well over $1000.00.
A standard anamorphic adapter stretches the picture horizontally so you would also need a second backup lens, about twice the focal length of your prime lens but the Scneider lens calculator referenced above will give you the right size. This is the easiest operationally as you would be switching complete lenses to change formats.
The last approach is to attach a reverse anamorphic adapter to your existing prime lens. This shrinks the picture vertically, the width remains the same so no second prime is needed. This is a pain operationally unless you have the space and bracket to mount the adapter as a swing-away or other method. having to screw it on to the prime every time would mean finding a way to set the angle or adjusting it visually on screen at the start of every scope film.
What I can't say for sure is whether a normal anamorphic adapter can be simply mounted backwards and work as a "reverse" way. My morning brain suggests "probably" but I've never actually tried it. If it does work (and someone here knows) that would be the most economical approach, used normal anamorphs are not too expensive - new reverse ones are.

Posted by Greg Mueller (Member # 17) on 02-20-2003, 09:10 AM:

I have a friend who says it was a fairly regular practice to reverse the anamorphic for drive in use. Jack probably has reference to that

Posted by Dave Macaulay (Member # 813) on 02-20-2003, 04:24 PM:

I tried reversing one and it does work. The one I tried didn't have threads at the "front" and would need a strange adapter ring at best if it did... but I think this would be the best approach if he wants the same width picture. One could find a way to attach it.
There's a Kowa anamorphic complete with 6.5" backup and a lens ring (looks like a 4 incher) on Ebay now at $10.00. (Hopefully that doesn't go against the "no Ebay links" rule [Smile]

)

Posted by Neil McGovern (Member # 1247) on 02-28-2003, 11:19 PM:

After suffering from buying the wrong size lenses a few times, we now simply call up the company we are buying the lens from and tell them our measurements.
It has the added advantage of if the lens is incorrect, we get a free replacement!