8mm Forum: UPDATED w/ 3-D printing - DIY Zoom Lens Project for ELMO 16CL Projector.

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Topic: UPDATED w/ 3-D printing - DIY Zoom Lens Project for ELMO 16CL Projector.

Terry Lagler
Jedi Master Film Handler

Posts: 525
From: Ontario, Canada
Registered: Apr 2008

posted June 25, 2015 12:38 PM

In my home set up the projector sits approx.. 12 feet from the 5 foot wide pull down screen.
No problem to fill the screen with my Super 8 projectors with their zoom lenses but a problem for my 16mm ELMO 16 CL with its stock 50mm lens. Until a get a proper lens I’m happy with my DIY solution.
I noticed that the barrel size of the lens from an old junked Kodak M-70 projector was pretty close in diameter. Also the inner element had a larger opening than other of the lenses I have.

Kodak lens on left

Instead of wrapping tape around the Kodak lens to get it to the correct diameter I found that 2 flat rubber “belts” from the drive gears of an old Bell & Howell 357 projector brought the lens barrel up to almost the exact diameter I needed. (wrapping electrical tape once around the barrel gave me a perfect fit)

Comaprison: you can see the wrapped electrical tape with flat rubber belts uses as support.

overlay of Kodak lens on top of ELMO: perfect diameter match for lens barrel.

Since the focus dial with the Kodak lens would be useless I found the rubber holds the lens in place once you get the focus correct by sliding the lens back and forth.

Here is my image size with stock Elmo lens on 5 foot wide pulldown screen with projector 12 feet away.

and

with the DIY Kodak zoom lens I can fill the screen (you will notice slight vignetting but I can't complain)

Here you can see the lens installed (with cover on in thumbnail)

Cheers
Terry

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Terry Sills
Phenomenal Film Handler

Posts: 1423
From: Weymouth,Dorset,England
Registered: Oct 2012

posted June 25, 2015 01:44 PM

Brilliant! Necessity is the mother of invention. I did a similar thing with my Buckingham 9.5 which is based on the Eiki Elf. I found that a Bolex Paillard Zoom lens was almost a perfect fit in the barrel. Like you I suffer a little vignetting but not too noticeable and it fills a 5' screen from a very short throw.

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Barry Fritz
Phenomenal Film Handler

Posts: 1061
From: Burnsville, MN, USA
Registered: Dec 2009

posted June 25, 2015 05:33 PM

Great job!

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted June 25, 2015 06:08 PM

A very nice retrofit Terry! You've come up with a feasible and economical DIY solution. Thanks for posting the how-to steps and pics. I have 2 16CL's one has the original 50mm lens and the second I bought a 25mm lens with an adapter sleeve. If I can locate a lens...I might give your method a try. [Smile]

--------------------
Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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Terry Lagler
Jedi Master Film Handler

Posts: 525
From: Ontario, Canada
Registered: Apr 2008

posted June 26, 2015 02:14 PM

Hi Janice.
I too was thinking about a 25mm lens. May I ask where you found your lens and sleeve.
Cheers
Terry

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Terry Sills
Phenomenal Film Handler

Posts: 1423
From: Weymouth,Dorset,England
Registered: Oct 2012

posted June 26, 2015 04:31 PM

I've sleeved a Specto 1" lens for my RCA Hollywood and it gives great results with no vignetting . You would probably need to look for a 16mm Specto for spares/repair to get a reasonably priced one. Good quality lenses.

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted June 26, 2015 05:47 PM

quote:
May I ask where you found your lens and sleeve.

I bought my lens from this guy http://www.ebay.com/usr/ohw?_trksid=p2047675.l2559 on Ebay for $130. It's was a very nice lens with no vignetting.

[ June 26, 2015, 07:05 PM: Message edited by: Janice Glesser ]

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Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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Terry Lagler
Jedi Master Film Handler

Posts: 525
From: Ontario, Canada
Registered: Apr 2008

posted June 27, 2015 09:54 AM

Thanks so much Janice.
That Global Shipping Program is a killer though!
Cheers
Terry

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Terry Lagler
Jedi Master Film Handler

Posts: 525
From: Ontario, Canada
Registered: Apr 2008

posted July 09, 2015 12:47 PM

UPDATE
My DIY method now has a significant improvement!
Shortly after posting this I went to an intro to 3-D printing seminar at my local library. The library has a grant for free 3-D printing that should last until the end of the year. I figured this would be an easy project to try it out since it only involves making a hollow cylinder with a cutaway for the focusing knob.

Here is the basic 3-D shape (of course it needed to be carefully measured to fit the projector and new lens)
I used 123D Design - a free download for the basic version.

Here is the printed lens sleeve beside the stock lens and Kodak zoom lens.

Sleeve fitted on lens

and fitted into the projector (without lens)

with lens

A nice snug fit and I can now use the focusing knob!
Also now that it is precision mounted the vignetting problem is greatly reduced.

Cheers
Terry

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted July 20, 2015 10:25 PM

Outstanding Terry! Just a thought....but perhaps you could provide the 3D file as a template so others could use it and modify the dimensions to fit their particular lens.

--------------------
Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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