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

This is topic UPDATED w/ 3-D printing - DIY Zoom Lens Project for ELMO 16CL Projector. in forum 16mm Forum at 8mm Forum.

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Posted by Terry Lagler (Member # 1110) on 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

Posted by Terry Sills (Member # 3309) on 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.

Posted by Barry Fritz (Member # 1865) on June 25, 2015, 05:33 PM:

Great job!

Posted by Janice Glesser (Member # 2758) on 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]

Posted by Terry Lagler (Member # 1110) on 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

Posted by Terry Sills (Member # 3309) on 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.

Posted by Janice Glesser (Member # 2758) on 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 ]

Posted by Terry Lagler (Member # 1110) on June 27, 2015, 09:54 AM:

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

Posted by Terry Lagler (Member # 1110) on 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

Posted by Janice Glesser (Member # 2758) on 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.

Posted by Terry Lagler (Member # 1110) on July 22, 2015, 01:19 PM:

Sent you a pm Janice.
Of course I'm happy to send the file to anybody who wants it.
Cheers
Terry

Posted by Janice Glesser (Member # 2758) on July 22, 2015, 05:49 PM:

Thanks Terry...I'll give it a go [Smile]

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