This is topic Help needed: 2x and 1/2x Anamorphics in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Pete Lawrence (Member # 130) on 03-11-2002, 09:25 PM:
I've been told that a normal 2x anamorphic adapter can be made to work as a 1/2x by simply reversing it. I've seen an example of an old B&L type 1 adapter, the BIG ones, mounted in reverse for drive-in use. When I try reversing my scope adapter I can't get it to focus. Throw is 23 feet and the screen is 10 feet wide for this test. The lenses I've been using are an ISCO Ultra MC 100mm prime and an ISCO Ultra Star HD 2x anamorphic attachment. This combination works great in the normal 2x mode.
The reason for all this is I work with a non-profit group that runs a sci-fi convention here in NY. www.iconsf.org One of the studios has offered to let us run several 35mm prints at no charge. This years film budget is shot so I have to do this with equipment I already have at little or no cost. The auditorium we have access to has a screen 16 feet wide at a throw of 68 feet.
Any help or suggestions would be appreciated.
Posted by Steve Guttag (Member # 268) on 03-11-2002, 09:44 PM:
The Ultra-Star HD anamorphic (5-element) is not designed to work in reverse. Furthermore, there is no good way to couple the lens from the front. Also most reverse anamorphics are used on longer throws, hence the need for the reverse anamorphic. The reverse mode is never as good as the forward mode. The image on a reverse tends to geometrically out of whack.Steve
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"Old projectionists never die, they just changeover!"
Posted by Gordon McLeod (Member # 33) on 03-11-2002, 10:19 PM:
If my memory is correct from the old kolmorgen stuff the focus scale is reversed
Posted by Steve Kraus (Member # 476) on 03-12-2002, 05:39 PM:
Can you reverse a Panatar?
Posted by Mark Gulbrandsen (Member # 72) on 03-12-2002, 06:38 PM:
Well you can reverse the space shuttle too but it'll crash! Why on earth would anyone want to reverse a Panatar???In using the long throw Isco reverse anamorphs I did notice a lot better definition than if a 2x were used. There was some distortion but it was not too bad.
Mark @ GTS