8mm Forum: Magnification for Cinemascope

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Posted by Dimitrios Kremalis (Member # 272) on October 13, 2005, 12:38 PM:

What is the ideal anamorphic lens magnification (horizontal) to view scope features? 2x, 1.75x or 1.5x?
Will a 1.5x scope lens desqueeze the frame appropriate?

Posted by Mal Brake (Member # 14) on October 13, 2005, 02:01 PM:

Hi Dimitrios, for commercial super8mm prints you need 2 X expansion. Mal

Posted by Jan Bister (Member # 332) on October 13, 2005, 07:57 PM:

Affirmative... Since super-8 has a 1.33:1 aspect ratio, scope prints bring 2.66:1 onto the screen, with (so I've been told) thin black bars on either side to accommodate the 2.35:1 ratio of the original negative.
I'd think you'd have a very hard time finding a scope lens with a stretch factor other than 2x, anyway. [Wink]

Posted by Dimitrios Kremalis (Member # 272) on October 14, 2005, 03:25 AM:

Thank you very much!

Posted by John Whittle (Member # 22) on October 15, 2005, 04:20 PM:

quote:
I'd think you'd have a very hard time finding a scope lens with a stretch factor other than 2x, anyway.

Actually there are lots of lenses in the 1.5 and 1.75x range. The 1.5x was widely sold for home movie makers, the Bolex anamorphic set was 1.5, many of the Vistascope lenses wer 1.5 as were some Japanese lenses like Sankyoscope.

The 1.75 lens was used on 16mm Inflite prints which provided a 2.35:1 aspect ratio from a 16mm frame and you'll occassionally see these turn up. They were made for Inflite by Kowa and Moeller and were very high quality lenses. There are still some 16mm Technicolor IB prints around that were made at the 1.75x ratio.

However, all Cinemascope prints were designed for a 2x lens (there were some other early processes that used other compression ratios like the first SuperScope which was 1.5x and the SuperScope lens which was a variable prism lens that accommated from 0X to 2X and could be "cranked" to the proper ratio with the lens installed on the projector so it could go to "0" for flat and to 2X for scope).

Beware of some of the Sankor (also engraved DO Industries and Eiki) 16C/F lenses on ebay which were modified by Laird for telecine use for their telecine bay which was sold to the US Navy for on ship television. These lenses have a compressed rear barrel so they focus at about 2 to 3 feet and cannot focus at regular projection distances (an anamorphic lens gets longer to focus further away). There are also some Buhl Anamorphic lenses floating around that are remounted Sankor optics without a focusing mount and can be set with an allen wrench. This permits final astigmatic correction and distance setting. Most lenses that look soft do so because the front and rear elements are no longer in proper alignment. Any offset angle will introduce softness in the image. A really good scope adapter will have good constranst and "snap" if the back up lens is good.

John

Posted by Jan Bister (Member # 332) on October 15, 2005, 09:38 PM:

Fascinating [Eek!]

Thanks for all the info John [Smile]

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