Film-Tech Forum ARCHIVE: Advice: Ultra Short Throw 16mm Projection

This is topic Advice: Ultra Short Throw 16mm Projection 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=011480

Posted by Michael Gerrity (Member # 7734) on 06-29-2013, 11:12 AM:

I'm a film student at The School of the Art Institute of Chicago and I'm getting ready to put on a performance with live 16mm projections. For the piece I would ideally like to place the projector about 8-10 feet away from an 8x6 foot screen (or larger if I can). I know this is an extremely short throw for 16mm, but I'm wondering if there are any projector/lens combinations or DIY solutions that would satisfy my constraints.

Thanks in advance!

Posted by Steve Guttag (Member # 268) on 06-29-2013, 11:15 AM:

20mm is about as short as I normally saw for 16mm projectors.

Posted by Jeff Taylor (Member # 443) on 06-29-2013, 12:26 PM:

...and with lenses that short you will need to watch out for vignetting, distortion, and other artifacts. Many of them are very slow, too. Good luck.

Posted by Scott Norwood (Member # 30) on 06-29-2013, 12:31 PM:

Is folding the light path with mirrors an option? Or rear projection?

Posted by Jack Theakston (Member # 4484) on 06-29-2013, 02:27 PM:

I'd agree with Scott that rear-projection is probably the way you're going to want to go with this, particularly if there's performing going on in the foreground.

Posted by Gordon McLeod (Member # 33) on 06-29-2013, 02:48 PM:

Buhl optical used to make some very short focal lens

Posted by Frank Angel (Member # 248) on 06-29-2013, 04:30 PM:

Years ago, Buhl custom made two .75in lenses for us for two Eastman 25Bs....you could focus only about 75% of the image in the center. It wasn't what I would call a raging success story.

As Scott suggests, rear screen is usually the way to go for those combination projects where you need to have live-action and projection together. It give you the option of using mirrors to expand the image to a decent size without necessarily needing to futz with esoteric lenses that are not off-the-shelf items. And with 16mm long gone as a thriving format, finding even off-the-shelf lenses for particular projector models is not an easy task.

Is it at all possible that you can use rear screen in your setup?

Posted by Jeff Taylor (Member # 443) on 06-29-2013, 04:41 PM:

I actually have a pair Schneider 30mm, or .78" lenses which are terrific. Of course they're Schneiders, and had I not made a steal on ebay I wouldn't own them. To pick up on an earlier comment, though, you'll frequently find right angle rear projection Buhls on the second hand market, and they're definitely intended for short throws. Sorry, but I can't recall the specs.

Posted by Richard Fowler (Member # 893) on 06-29-2013, 06:37 PM:

What brand of projector.....on museum displays I have used an auxiliary magnifier mounted on an adjustable arm on a plate in front of the prime lens.

Posted by Steve Guttag (Member # 268) on 06-30-2013, 12:16 AM:

I found that the Buhl lenses to be VERY wanting...they catered to the A/V world that needed something that fit...they never traded on being really good.

Posted by Richard Fowler (Member # 893) on 06-30-2013, 09:33 PM:

Buhl traded on being 1st with a solution when there was nothing to reference to....military optics where a large part of their output.

Posted by Michael Gerrity (Member # 7734) on 07-01-2013, 01:08 AM:

Thank you so much everyone for your help! I really appreciate it.

Rear projection is not an option since I will be rear projecting video onto the screen as well. For the performance I want the film images to overlay the performers, and the film projector is very much apart of the piece.

Although I would like to get the image as crisp as possible, it's not the end of the world if it's not perfect. I'm blowing up some super 8 footage to 16, but otherwise the images are going to be pretty grungy and experimental. Someone on another forum suggested I get a wide angle lens adapter that's used for video cameras and put that in front of the lens. They said a X .75 lens would give me a 50% increase in image size, and a X .5 would give me a 100% increase. Does anyone have experience with this?

Posted by Leo Enticknap (Member # 534) on 07-01-2013, 04:40 AM:

Schneider do a 10mm lens, but it ain't cheap.

There are some people who fit the zoom lenses supplied as standard with Super 8 consumer projectors into sleeves to enable them to fit into 16mm machines. However, the resulting quality is a bit of a crapshoot. I'm got a Eumig 18-30mm zoom in a 42.5mm sleeve for my Eiki portables, and it's actually not bad. In our campus theatre (horseshoe-shaped auditorium), which has around a 10m throw to a screen that's about 4m by 3, you can just see a little bit of vignetting around the edges if the print being shown is very crisp and sharp and you're really looking for it; but otherwise I'm quite impressed with it.

However, when I explained this to a visiting experimental filmmaker (who only had the standard issue 50mm lenses on her projectors), she went and bought one on Ebay. The lens in the collar was a no-name one: the vignetting was seriously bad, and it absorbed a lot more light, too (she came in and we did a side-by-side comparison).

Posted by Jeff Taylor (Member # 443) on 07-01-2013, 09:15 AM:

One person who does rebarreled 8mm and 16mm lenses as Leo mentioned is Omer Whayne. He does nice machine work. You can track him down via 16mmfilmtalk. Good luck.

Posted by Phillip Grace (Member # 2262) on 07-02-2013, 04:36 AM:

Hi Michael
I tried using camera type adaptors to increase the focal length of a projection lens at one time. The flare and vignetting completely killed the image. I suspect that these attachments are not meant to cope with the high light levels found in projection.
Buhl also made very short lenses for direct projection, as opposed to reversed. The Buhl reversing lenses I have seen all appear to consist of a short focal length projection lens in combination with a magnifier. The 90 degree reversing element between them is just a first surface reflector inside the housing. I'm suggesting that you could re-work one of their 16mm reverse lenses into a direct projection one without too much grief. Just looking at the throw/image size dimensions you suggested, I think you will need to place the projector a bit further away to get that large an image under any conditions.
The diameter of the lens mount on the projector is a consideration. Some series of 35mm lenses in short focal lengths will fit in (sleeved) and focus. They are usually easier to find than the 16mm equivalents.

Cheers.