Film-Tech Forum ARCHIVE: Vertical Fold-over with Schneider Anamorphic Lens.

This is topic Vertical Fold-over with Schneider Anamorphic Lens. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Paul G. Thompson (Member # 655) on 12-25-2003, 05:30 PM:

I am presently plagued by this phenomena with an anamorphic lens. It looks like what you will see on a vertical sweep of a smellivision set when the coupling capacitor to the vertical output driver is breaking down.

I know it is the anamorphic lens that is causing this. I have a late model Schneider Anamorphic lens.

I have to place a hunk of masking tape to the projection porthole to keep it off the screen. It is extremely obnoxius during credit rolls at the end of the movie.

What can I do other that blowing an astromonical amount of money on a new scope lens? I have seen this once before many years ago, but I was a puke in a position where I could not do anything about it.

Posted by Steve Kraus (Member # 476) on 12-25-2003, 06:07 PM:

Are you sure it's the Scope and not damaged backup?

Posted by Paul G. Thompson (Member # 655) on 12-25-2003, 06:14 PM:

Steve, it is the scope attachment, almost positive about that.

Posted by Steve Guttag (Member # 268) on 12-25-2003, 06:36 PM:

Are talking about seeing a reflected image just ouside the picture or a double image? Normally this caused in the gate area and the anamorphic lens is just projecting it. I must admit...I've never had a Schneider lens do this to me but who knows.

Steve

Posted by Phil Hill (Member # 371) on 12-25-2003, 06:44 PM:

Yes... please speak in English so us un-enlightened can understand what you are seeing... [Big Grin]

>>> Phil

Posted by Mark Gulbrandsen (Member # 72) on 12-25-2003, 06:46 PM:

I had it happen only once in at a new location...oddly it was also a Schneider anamorphic and in this case the lens was not to blame. Even though the proper angle for the port glass was on the blueprint this location installed their port glass wrong, straight up and down, and it could not be changed without alot of work. It was simply a reflection off the port glass(starphire in this location), back to the front element and back out again. Offsetting the machine a couple of inches and then using the turrett adjustments to put the image back on center again stopped the reflection. It was only visible on extremely bright scenes and about 1/3 of the total width of the image over to the left side of the picture in this case.

Try removing your port glass to see if it disappears. If not then move lenses around and see if it travels with that suspected lens. You know the rest of what you'll have to do from there.

Just so you're aware, Schneider scope lenses, all of Schneider's lenses are repairable at Schneiders subsidary, Century Precision Optics in Burbank. If you need an element or element group that is not in stock it can take quite a while as they have to make them in Germany.

Mark

Posted by Paul G. Thompson (Member # 655) on 12-25-2003, 10:20 PM:

Steve, it was a double image about 12 inches from the top of the screen. The top part (about the 12 inches worth) of that image scrolled down at a much lesser intensity while the credit images scrolled up. Very weird.

Posted by Steve Guttag (Member # 268) on 12-25-2003, 11:21 PM:

Paul:

Two things...remove the port glass (as Mark suggested...it is the most likely) and also remove the aperture plate...Kinoton's with their chrome plates can cause some double images if the light angles work out just right...even non-coated shutter blades can do it. I really doubt it is the lens itself that is generating the image...it is "seeing" something and dutifully sending it down.

Steve

Posted by Paul G. Thompson (Member # 655) on 12-26-2003, 03:27 AM:

Unfortunately when the theater was built, the porthole glass was made non-removal. [Mad]

However, the roll-over can be seen on the masking tape we have to use to keep it off the screen, so I don't think it is being caused by the porthole glass itself. The problem does not exist on flat movies.

Steve brings in an interesting thought about the aperature plate reflection. I'll pull the plate during the credits and see what happens. I wonder if someone dropped the lens at one time. As I think about this it seems as though some time ago, the problem did not exist on scope movies. All of the sudden it did. I'll swap out the scope lens just to see what happens.

Since this is a wierd problem, I'll pass along what I find.

Posted by Steve Kraus (Member # 476) on 12-26-2003, 09:31 AM:

I think this calls for a betting pool. Put me down for prime lens issues. [beer]

Posted by Paul G. Thompson (Member # 655) on 12-27-2003, 02:11 PM:

Steve Guttag was correct. It was the aperature plate.

Posted by Steve Kraus (Member # 476) on 12-27-2003, 11:13 PM:

Why did it suddenly start doing this?

Posted by Paul G. Thompson (Member # 655) on 12-28-2003, 12:12 AM:

Steve K, it looks like it was sprung and straightened by with a hammer. The bottom edge of the opening was rolled over a little, and apparently was providing a light reflection. I'm going to try to trim it iup a little, but since it is a full 2.35 cut already, I don't have too much faith in being successful.