Film-Tech Forum ARCHIVE: Missaligned projectors- Help!

This is topic Missaligned projectors- Help! in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Kyle Butler (Member # 5601) on 05-04-2010, 04:29 AM:

Long story short, a few of our previous projectionists didn't realize that our PR1050'S had vertical/horizontal adjustments for the lens mounts.
The L/R position of the picture over time had moved a few inches on screen (I'm assuming from people using the lenses as handlebars to kneel and thread the projector)

Their solution?: Move the whole projector.

Problem?: Most of our screens now have a decent amount of keystone, and its physically impossible to focus both the left and right side of the image at the same time.
So everything has to be what i would call "Center focused"
So the whole image is slightly out of focus VS having one side looking great and other looking like crap. I won't even start with what a pain in the butt it's made lamp focusing.

So here's the question:
What is the correct procedure for re-centering the projector on screen?

Any help at all is greatly appreciated.

PS: We use a mix of Highlight, Xetron, and Christie consoles, all with TU2000 or PR1050 heads.

Posted by Michael Voiland (Member # 5386) on 05-04-2010, 08:23 AM:

You are going to need to move the projector back. Look for marks on the floor where the projector was and try to line it back up. Also there is probably a problem with your lens if you cannot obtain an even focus.
Check out the focusing anamorphic tips
http://www.film-tech.com/warehouse/tips/anamorphics/anamorphics.html

If the lens is physically damaged aka bent it will not produce a good image. Also if some of your projectionist are using the lenses as a handlebar maybe proper lens handling training is in order.

Posted by Louis Bornwasser (Member # 3063) on 05-04-2010, 09:48 AM:

The only way is to align the lens to the gate, then align the projector to the lamphouse, then reaim the whole thing on the floor.

Any other procedure will give divergent results. Louis

Posted by Jeremy Weigel (Member # 4208) on 05-04-2010, 10:38 AM:

What's the easiest way to align the lens to the gate? What "tools" are needed?

Posted by Kyle Butler (Member # 5601) on 05-04-2010, 08:23 PM:

Trust me, Ive been over the standard do's and donts with the booth
monkey's several times.
In order for them to stop messing with the lenses, they would have to care about anything. -_-
I have no control over making them do so.
Therefore i have to suck it up and fix the screw ups.
Not a big deal, as long as its something manageable.
This however seems a little beyond me.

And the focus issue isn't related to anything in the "focusing anamorphics" page. I have several screens that need that procedure done, so i know that isn't the case with these particular screens.
Its basically an intentional soft focus to accomodate the fact that the throw distance from the left side of the screen is now significantly shorter than the right.

Ive attempted to move them back where the marks on the floor would indicate they should be with decent results.

I was just quesitioning (as a total booth rookie obviously) if there was a set in stone procedure for positioning the projector.

I mean, how did they center it when it was first installed?
That way, that particular procedure could be repeated for optimal results.