Film-Tech Forum ARCHIVE: Adjustable pedestal for 35 flat v. scope optical centers

This is topic Adjustable pedestal for 35 flat v. scope optical centers in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by David E. Nedrow (Member # 4981) on 04-10-2009, 10:43 PM:

Has anyone ever seen a 35mm projector pedestal that had a crank arrangement and a movable plate such that the projector could be adjusted for the differing optical centers of flat and scope films?

I've heard that there were some pedestals manufactured like this, but have yet to come across one or even a picture for that matter.

-David

Posted by Stan Gunn (Member # 554) on 04-11-2009, 02:32 AM:

A very common device 50 years ago,but think about it.the centre of the image of any format is always the same.

Stan [Big Grin]

Posted by Phillip Grace (Member # 2262) on 04-11-2009, 02:33 AM:

The top plate of the Super Simplex LL-1 pedestal c. 1937 has this adjustment. It may be panned sidewise by a few degrees using a lead screw arrangement. There is also rudimentary scale to allow pre-positioning. This pedestal is adjustable in just about every respect, and is of massive cast iron construction. Being pre-cinemascope, the adjustment was provided for focusing the projector on one or more screens (further upstage or downstage, I assume) in a movie palace situation, and would have been useful re-centering for silent aperture. The more usual, and still current approach for recentering for (magnetic) Cinemascope centre line, or silent film, is to provide some means of moving the optical centre of the projection lens sideways. An eccentric collar around the lens barrel is the most common solution. Otherwise the whole lens mount is made adjustable.
Cheers! Phil.

Posted by Stan Gunn (Member # 554) on 04-11-2009, 02:37 AM:

Hi Phill better said but I just mowed the lawn,

Posted by Phillip Grace (Member # 2262) on 04-11-2009, 02:39 AM:

G'day Stan! Absolutely right! All 35mm projection formats now have the same optical centreline.

Hello to Marg, Marnie and Bella. Oliver sends a rat.

Posted by Robert E. Allen (Member # 1351) on 04-11-2009, 04:21 PM:

quote: Stan Gunn
A very common device 50 years ago,but think about it.the centre of the image of any format is always the same.

Hey Stan:

"Back in the day" I worked several houses where I had to adjust the projector angle to go from flat to 'scope. The bases all had height adjustment wheels with marks for each. Simplex, Century, Ballantyne, Motiograph, Brenkert all made bases that were adjustable for height and the Super Simplex (as has been pointed out) was also adjusted horizontally. I'm sure a bunch of these are still sitting around collecting dust in someone's storeroom.

Posted by Richard B. Perrine (Member # 409) on 04-11-2009, 10:42 PM:

David....check in with the guys who take care of the Palace and the Ohio....
It's been a few years, but they had some spare machines around there and a couple of the bases.
Look for the Simplex base.
If you want a copy of the catalog...send me a PM and I'll copy it and mail it to you.

Posted by John Eickhof (Member # 323) on 04-12-2009, 08:57 PM:

The LL-1 was adjustable for silent / sound picture centers, also the RCA light duty enclosed pedistal as well as several BF Shearer types were also adjustable horizontally. Plus there were kits for most projectors after mag only prints came out to adjust the lensholder side to side, to compensate for the different optical center of mag vs regular optical soundtracks. I have them for the Standard, Super, E-7 and XL Simplex, the Brenkerts often had the adjustment kit from the factory and LaVezzi made a kit for the Century C & H models, and the SA had it built in at the top of the lensholder.

Posted by Jim Cassedy (Member # 4115) on 04-13-2009, 01:02 AM:

quote: Phillip Grace
The top plate of the Super Simplex LL-1 pedestal c. 1937 has this adjustment. It may be panned sidewise by a few degrees using a lead screw arrangement.

Here's a couple of actual pictures. (WoW!)
I'm not sure exactly what model this is, but it is a
Simplex Pedestal in a theater which dates back to 1937.
The wheel in the back controls the elevation. (tilt)
There are also two large thumbscrew-like thingys.
The rearmost one locks the tilt mechanism.
The one forward of that moves the top plate laterally.

This ped supports a 35/70 Century JJ and 4k lamphouse.

Here's a similar one in another 1930's vintage theater.
This one is "original" and hasn't been painted tacky silver.

Another thing I like about these old peds is that they
have a built in spirit level.

Posted by Mike Croaro (Member # 3123) on 04-15-2009, 06:32 PM:

Hi Folks:

I thought they still used those pedistals in installations sometimes? Like in smaller independent theatres. I worked in three theatres that had them.

Mike

Posted by Monte L Fullmer (Member # 2797) on 04-15-2009, 09:04 PM:

...and when you take them bases apart, that quite a bit of plate steel and cast you need to haul around...

Those were the best bases to use when fine tuning in two machines.

The one booth that I had as a chief operator has basically the same configuration - turnstiles to use for pitch along with pivoting the base left and right to aperture center to go between flat and scope - due to that we had adjustable top and side tabs for flat - from 1.66:1 to 2.00:1, and with scope from the standard of 2.35:1 to full mag 2.55:1 usage..all with their respective apertures.

Posted by Tony Bandiera Jr (Member # 2365) on 04-16-2009, 02:17 PM:

quote: Stan Gunn
A very common device 50 years ago,but think about it.the centre of the image of any format is always the same.

As much as I wish we lived in a perfect world, I have found that on a two-projector setup scope and flat don't always line up exactly on center...at UC Irine the difference is bad enough on my #2 projector that I have to kick (literally) the machine a few inches to re-center my scope image. No easy task with the FP-18 hanging on the back door and the double lamphouse set-up.

I attribute this problem to three things:

One, the horrid triple lens turrets on each projector. Although Kinoton makes some good stuff, I have some doubts about the accuracy of the centering of each lens hole in relation to the aperture and optical center of the film path.

Two, if the backup lens is not EXACTLY the same focal length as it's mate, there will be subtle size differences that will affect the centering of the image because of the different magnifications. Any pair of lenses used for two-projector setups must be matched within 0.5mm to be safe....I believe that the normal manufacturing tolerance on lenses can be as much as +/- 1.0mm or more.

And finally. our old friend of two-projector setups, keystone. My #2 machine is further off the center line of the screen than #1.

I was able to go into the excellent booth at UCLA, they had build custom "padds" for their Kinotons that had gearmotor driven pivot mechanisms, complete with calibrated scales so they could preset the projectors accurately without ever having to put light on the screen. They also had the single-lens mounts which, once lenses are set up correctly, hold focus during lens swaps. *sigh* I would give anything to get those mounts for my machines so I can throw those hideous turrets and aperture changers into the dumpster.

Posted by Louis Bornwasser (Member # 3063) on 04-16-2009, 09:35 PM:

Tony; if you can swing the lens "door" or move the lens mount, the scope will move left to right twice as fast as flat. You can always make the left/right centers agree if you can "cheat" the lens mount some. Louis

Posted by Scott Norwood (Member # 30) on 04-16-2009, 09:53 PM:

quote: Stan Gunn
A very common device 50 years ago,but think about it.the centre of the image of any format is always the same.

Not if you run silent, magnetic Cinemascope, or 70mm films.

Posted by David E. Nedrow (Member # 4981) on 05-17-2009, 11:34 AM:

Dang, I'm not sure how I missed these replies. Actually, I do. It's the way the forum automatically marks everything read as soon as the forum is viewed.

Thanks for all the info.

Scott hit the issue on the nose. We will definitely be running silent films during the year, and possibly magstripe 'Scope as well.

Posted by Steve Guttag (Member # 268) on 05-17-2009, 01:48 PM:

Do you have a Simplex 35/XL projector, by chance?

Steve

Posted by Tony Bandiera Jr (Member # 2365) on 05-19-2009, 01:53 PM:

quote: Louis Bornwasser
Tony; if you can swing the lens "door" or move the lens mount, the scope will move left to right twice as fast as flat. You can always make the left/right centers agree if you can "cheat" the lens mount some. Louis

Louis, thanks for the tip..I did discover something very interesting recently: the down angles on my machines are not the same. That and the adjustment of the lens turret stops may be what's causing the problem.

Each lens position on the turret has a stop plate that the lock pin goes into, it can be shifted a few degrees to either side.

My next move is to set the down angle on #2 to match #1 (which I never need to shift), then play with those stop plates to get the lenses to index to the same spots.

Posted by Michael Brown (Member # 890) on 05-20-2009, 06:41 PM:

quote: Tony Bandiera Jr
at UC Irine the difference is bad enough on my #2 projector that I have to kick (literally) the machine a few inches to re-center my scope image.

Had to do that back when I worked at a college cinema. We only had one machine (a westar) but the plates hadn't been cut perfectly. When going from flat to scope the pedestle had to be kicked (literally) a few times to the left. (and then to the right when returning to flat).