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Topic: Focusing Anamorphics

Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 08-11-1999 04:27 PM

I was reading the section of this site about focusing your 'scope lenses:

Here at TT17, we have the Schneider lenses where you slide the focus ring in and out to lock or unlock the lens. Since we have a few less-than-intelligent people who use the 'scope lens as a handle for turning the turret, (Century), the lenses get thrown off quite regularly. Since I have the blueprints to the building, I just set the lens back to the distance indicated on the drawings. I see, now, there is a better way...

My question is this: (Forgive my appearent stupidity)

What are you doing to the lens when you set the distance? I have heard people call this 'astigmatism'. My guess is that you are moving the focal point (node) of the lens back and forth until it is in the exact optical center of the anamorphic prism.

Once I get them back to the right settings I plan to mark the focus collar for ease of resetting. (AND I will tie a piece of polyester film around a very SENSITIVE part of the body of any one I catch using the lens as a handle and hang them upside down from the light pole in the parking lot!! )

Thanks for the input,

Randy

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Jim Ziegler
Jedi Master Film Handler

Posts: 753
From: West Hollywood, CA
Registered: Jul 99

posted 08-12-1999 02:06 AM

Your lenses may have some sort of locking screw to prevent them being adjusted by the stupid. You might check any documentation you recieved with the lens to find out for sure.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 08-17-1999 04:10 PM

Worse are the schnieder ones that have the little black knob on the front or the allen key hole and a quarter turn does the extremes of adjustment
Also has anyone been having problems with schnieder anamorphics going soft with time

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 08-17-1999 06:18 PM

I personally haven't had a problem with the Schneiders. I like the knob on the front better than the large focus ring of ISCO lenses. I find they are easier to fine tune without slipping during tightening.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 08-17-1999 08:15 PM

I definitely prefer the Schneiders with the twist lock on the front as well. You can easilly tell if it is locked or not. With the ISCO's it's kind of "touch and go", I guess, and you can mess things up easilly if you are not too careful. I also like the image quality of the Schneiders.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 08-18-1999 03:41 PM

I DO like those lenses except for the fact that they are easy to throw out of whack. (I'm looking for a locking screw. They are hard to find in the dark, ya' know.

)

The thing that brought the whole question to mind was that I was taking my girlfriend to see Star Wars last week and it was out of focus. I sneaked upstairs to tweek it and it wouldn't focus. Next day at work I went back and checked and sure 'nuff, outta' whack!

Anyway, I'm going to have to go though every projector and check them. They are all probably messed up again.

PS: The "sensitive body part" I was talking about was TOES!!

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