Film-Tech Forum ARCHIVE: Century C..cant open gate with lens in!!

This is topic Century C..cant open gate with lens in!! in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=007860

Posted by Richard May (Member # 2627) on 03-12-2006, 04:55 PM:

Okay guys. Never came across this one. I converted a screen the other day and put in a Century C head. Very short throw, maybe 30 feet. Problem is, the lens has to go so far into the lens barrel that it wont allow the gate to open. They have to take out the lens to thread up and put it back in. It is not hitting the lens collar. It is hitting the actual lens. Also, it is a small diameter lens inside an adapter and then inside a collar. The "tube" of the gate is hitting the actual lens. Any thoughts???

Posted by Mark Gulbrandsen (Member # 72) on 03-12-2006, 05:00 PM:

This is a VERY common problem with all older machines using short focal length lenses! 2 Choices.... 1. Put on a Kelmar Turret retrofit or... 2. Send the gate plate to Wolk and they will machine it out to clear the lens as best as is practical. Still may not work though...depends on lens back diameter and lens depth in barrel. Turrett conversion may ultimately be the only way out.

Mark

Posted by Stephen Frazza (Member # 2320) on 03-13-2006, 02:34 AM:

I had the same problem with a Simplex XL.
So this may be of no use to you because I have never worked with a century and couldn't tell by looking at the manual if it was similar.

But I took out the release lever and grinded it down with a dremel.
I only had to get a little off, just so it could catch the groove
on the operating lever without having to push the gate so far open.

It shortened the span of the gate when it was open slightly but it was still enough to work with.

Posted by Steve Guttag (Member # 268) on 03-13-2006, 07:48 AM:

You can also go the route of a longer focal length lens with a zoom converter to achieve the desired focal length.

Posted by Mark Gulbrandsen (Member # 72) on 03-13-2006, 08:17 AM:

quote: Steve Guttag
You can also go the route of a longer focal length lens with a zoom converter to achieve the desired focal length.

Been there done that... with the Schneider convertors way too much image distortion is introduced. There may also not be enough range available. The converters are light efficirent but introduce other noticable anomolies.

Mark

Posted by Louis Bornwasser (Member # 3063) on 03-13-2006, 08:19 AM:

If you are able to accept that the gate will not fully open, it may be possible to reposition the "opening knob" to allow a "half-open" condition. (See Simplex comment above.) This is a simple modification. (Yes, this problem is common with old projectors and new, short fl lenses.) Louis

Posted by Richard May (Member # 2627) on 03-13-2006, 09:21 AM:

will a magna com lens on a longer focal length lens do it? That may be our only option here. He will not spend money to retrofit the barrel. Any distortion on screen from zoom converter will be fine with him. All he wants is a picture on the screen. lol. Thanks again guys!!!!

Posted by Gordon McLeod (Member # 33) on 03-13-2006, 09:46 AM:

I have found that the Kelmar turret has issues with some short focal length lens as well so it isn't the best fix

Posted by Mark Gulbrandsen (Member # 72) on 03-13-2006, 07:09 PM:

You would have to try the magna-comn and see. If this is a short throw then the Zoom Comnverter may be the best but fairly expensive option. Also try what Loius mentioned. Had to do it on my VistaVision projector to get the gate to function correctly. I also drilled new "dimples" in the collar once the correct position was found.

Mark

Posted by Richard May (Member # 2627) on 03-15-2006, 05:38 PM:

Magna com worked perfectly. Was actually able to get correct size on screen now for flat. Thanks everyone for your help. [beer]