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Short throw lens for gs 1200? Help!

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  • Short throw lens for gs 1200? Help!

    When I moved to my home in Florida and set up my theater, a strange and disappointing problem happened. Although I understand the reasoning, it is unfortunate that I cannot at this time use the larger screen that came from the basement in Massachusetts. The screen is 4 feet by 10.5 at my parents’ home with a throw about 26 feet.

    To use it properly here in Florida the throw is less distance at 17 feet. To resolve this temporarily I increased the size of the masking frame. This material was placed over the original. To remove the new masking is easy and will restore the screen to the basement size. The current remasked screen is 38 inches high by 9.25 feet wide. The ratios are great and proper, but smaller.

    To open to original larger size is my goal. I will need a short throw lens to fit the GS 1200 to do it. The idea is to fill the 4-foot height with less zooming of the barrel.

    The pictures attached show my problem.

    With the original screen opened and the standard GS1200 equipped lens zoomed out, the flat height works great.

    The problem is with the Goldie Isco Optics 2X 35mm lenses.

    Inside this lens barrel are vertical construction. The outside corners of the super 8 frame are hitting these vertical posts thereby causing shadowing on the screen. At that size, it is nasty and unwatchable.

    A shorth throw lens that can zoom out as big but stay inside the vertical posts would be ideal.

    The projectors and/or screen can’t be moved.

    Any advice would be greatly appreciated.

    I have sent a letter to Ed Van-eck. However due to the pandemic I think his office is closed which is understandable. Does anyone have personal contact with him perhaps he could log in and check emails from home?

    I am in love with this hobby of film collecting. Understanding the nature of the format’s flat vs cinemascope whereas the height stays the same and only the width changes is my goal. In my experience as projectionist I worked some locations where they did not do that. Because of poor construction of splitting a large single theater to a long narrow cracker boxes – it yielded the opposite where the height changes, but the width did not. Although yes this preserved the original scope ratio, I never cared for this and will NOT do it at home. Because YES it would be possible to have a taller flat image and smaller scope height with proper width (2.66) but again, I will not go that low to do this.

    I have several pictures will try and attach below.

    Thank you in advance for your support.

    Click image for larger version

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  • #2
    Are you using the Elmo 25-50 zoom ?
    Van Eck answered one of my e-mail last Saturday. I don't know if, meanwhile, they closed.


    • #3
      I am using the better lens that came with the GS 1200 the standard GS 1200 lens


      • #4
        I am not sure about your last reply. According to Van Eck's site the Elmo GS-1200 has a choice of two basic lenses:-
        f1.2, 25-50mm
        f1.0, 12.5-30mm



        • #5
          The standard lens for the GS is the 1.1 12.5-25mm. Only the Xenon came standard with the 1.2 or 1.0. The only other option that I know of for a shorter throw lens would be a Schneider 1.1 11-30mm. They made one for the Elmo but almost impossible to find. So you can see if you can find the 28mm barrel diameter For the Bauer series and use a sleeve. I don’t see how a short throw lens - meaning one that gives you a larger picture at a shorter throw will help. If anything you will get more vignetting.
          Last edited by Alan Rik; April 08, 2020, 05:28 PM.


          • #6
            I just checked my GS 1200 machines the lenses I have are 1.1 /. 12.5 - 25 mm


            • #7
              Problem might be solved I found scope lenses without the vertical obstruction have to open up the screen and test it. It might work or might not.....will report back soon


              • #8
                Problem solved works dandy!