Film-Tech Forum ARCHIVE: Poor Focus Right Hand Side of Screen

This is topic Poor Focus Right Hand Side of Screen in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ian Bailey (Member # 1752) on 06-15-2004, 08:49 AM:

Hi
I have a Simplex with a Kelmar Gate/Trap/Turret.Can't get good focus(in W/S & C/S)on the right hand side of the screen.Could this simply be that both lenses need to be adjusted horizontally and then the projector repositioned.Screen size is 18ft wide with about a 26ft throw.I know from a previous thread that Mark G. mentioned about using Kelmar Jigs with this Turret,is that the only way to go about it?
The other problem with this setup is intermittent picture shake-one show rock steady,the next with the "shivers".I've ordered new bands for the gate and trap(the old ones feel like they are not tensioned equally and are showing signs of wear).Should this improve the picture shake and is there anything else to check?
[thumbsup]

Thanks

Posted by Darryl Spicer (Member # 711) on 06-15-2004, 09:14 AM:

Does the projector sit at an angle or is it straight on to the screen? Is the shake a jump or a weave. Weaving can be caused by a couple of things. A shaky lens turret or loose lateral guide rollers. If the projector is at an angle it is key stoning and the focus may be a problem in those instances. Some small amounts of keystone focus issues can be adjusted out by shimming the lens in to a slight offset position. I have seen this done before.

Posted by Gordon McLeod (Member # 33) on 06-15-2004, 09:50 AM:

You may want to replace the gate bands if one is worn more than the other an uneven focus will result

Posted by Dominic Espinosa (Member # 2122) on 06-15-2004, 12:43 PM:

It may be possible that the lens is just loose or mounted improperly.
I know it sounds dumb but I've seen in before.

Posted by Ian Bailey (Member # 1752) on 06-17-2004, 03:02 AM:

Darryl the projector is square to the screen,the picture shack is most noticeable in the Credits-I watched the same show finish twice the other day and the first one had steady credits and the second you could see the slight picture shake.
The focus problem I feel could be the bands,as Gordon mentioned(which I will replace as soon as I get them)but if not it could be both lenses are not set correctly horizontally but I'm not sure whether I need jigs or not to set the turret.
Dominic-the lenses and the turret are not loose or moving.
Thanks

Posted by Mike Pennell (Member # 1692) on 06-17-2004, 04:49 AM:

Ian is the problem happening on both flat and scope?

Posted by Paul G. Thompson (Member # 655) on 06-18-2004, 01:05 AM:

Sounds like the guide posts for the shoe are sprung. Had that happen to me about 7 years ago. I "wanged" them back with a nut driver slipped on to the shaft. One side of the shoe was making heavier contact than the other side.

If you detect this sprung guide posts on a good visual inspection, the error you see should be obvious a keen eye.

If you think you can "wang" them back, be very careful. If you whomp it too hard, you'll have a handful of peanuts.

By the way, Gordon's comment may be well worth looking at.

John Westlund also had a problem just like that with his Century. Turns out the entire back casting (called the GIB in the manual I was looking at) was sprung.

If you have a guide pin missing on the back piece of the film trap or if there is a hunk of crap wedged between it, you will definately have one side in and one side out of focus.

Posted by Peter Hall (Member # 695) on 06-18-2004, 02:09 PM:

Try decreasing the lamp current drastically - if still there this will eliminate lamp focus/ heat. Is is worse on black backgrounds ? If so look at lamp and heat problems..