Adapting a projection lens to a studio light

David Brown · Nov 3, 2018

I have need (desire) of a very concentrated, but not necessarily bright, light source for small still life setups. A slide projector would work, but it is difficult to position and awkward on a light stand or tripod. However, a projector lens on a studio light fixture might do the trick. I have thought that scavenging a mount from an old carousel type projector and adapting it for the front of a light might be the ticket. (I already have five different lenses I can use.)

Any thought on how to go about this/ Anyone done anything similar?

Cheers,

AgX · Nov 3, 2018

David Brown said:
A slide projector would work, but it is difficult to position and awkward on a light stand or tripod.

There have been special plates to mount on a camera tripod to accept a projector, but yes, for horizontal projection.
But fixing a large camera-plate to some wooden board and mounting a slide projector onto that, in a way it cold not slide off, should not be that of a problem. If a heavy duty camera tripod with head is at hand (and not used for the camera taking that still-life) using a slide projector should be a reaonable makeshift solution.
At least over here the latest projector models all got a plastic cover and are quite lightweight.

WilmarcoImaging · Nov 3, 2018

It sounds like you are looking for a directional light source, is this right?

Suggestions:
- snoot on a studio strobe, placed a fair distance away from the subject
- narrow angle grid on a studio strobe, same placement as above
- fresnel light source, example here: https://newjersey.craigslist.org/ele/d/altman-lightingwatt-quartz/6734749966.html

jtk · Nov 3, 2018

I've seen something like that done on architectural models with common flashlights...

Consider "painting with light" technique. Today's high-intensity, ultra-cheap flashlights could be choked down to cover a small area, while held at enough distance to get out of the field of view.... Probably no need for a projector.

Long exposure, overall set lighting and then spot lighting as desired with the flashlight.

AgX · Nov 3, 2018

However a slide projector yields high-end light evenness in comparison to a flashlight.

jtk · Nov 3, 2018

AgX said:
However a slide projector yields high-end light evenness in comparison to a flashlight.

He doesn't seem to be looking for "high-end light", may be looking to softly add in a small area to the overall light on his model. As well, the new high-intensity flashlights seem very even due to the many LEDs.

IF he's looking for a sharp-edged spotlight effect that slide projector idea would be one answer...

WilmarcoImaging · Nov 3, 2018

Now that a flashlight is mentioned...

Flashlight velcroed or taped to a light stand, with a homemade directional emitter, to wit: a drinking straw snoot fitted in front of the flashlight. With or without a diffuser such as opal film or translucent paper. Experiment with drinking straw length and amount of translucency. The drinking straw snoot can be found using Google.

A small diameter LED high intensity flashlight might be what you are looking for.

David Brown · Nov 4, 2018

AgX said:
There have been special plates to mount on a camera tripod to accept a projector, but yes, for horizontal projection.
But fixing a large camera-plate to some wooden board and mounting a slide projector onto that, in a way it cold not slide off, should not be that of a problem. If a heavy duty camera tripod with head is at hand (and not used for the camera taking that still-life) using a slide projector should be a reaonable makeshift solution.
At least over here the latest projector models all got a plastic cover and are quite lightweight.

I have actually done this. However, tilting the projector at more than about 20 degrees starts adding it’s own problems.

There are snoots with fitted lenses for fresnel lights. (I do have a few old fresnel lights.). I guess I should have been more specific. I am looking form the same effect a stage spotlight with a very defined beam would make on an empty stage, but in miniature.

EDIT: I should have used the term “follow spot”. Anyway, I am not looking for alternatives. I just wondered is anybody else had thought of adapting projection lenses.

Mr Bill · Nov 4, 2018

Hi, yeah, I've designed a few somewhat crude projectors for various uses. The way you do things sort of depends on exactly what you want to do with the light, and how much money and effort you are willing to put into it.

You mentioned using a slide projector, but mounting it, etc., is a problem. Well, I would go along with AgX; it's easier to build a mounting fixture for the slide projector than to rig up your own projector. If necessary, pull the guts out and remount on your own baseplate, or whatever.

The method I think you are considering is to use your own projection lens with a focused "slide," perhaps just a metal plate with a hole cut in it, placed in front of one of your light heads. The problems with this are that 1) it's very inefficient, perhaps only 1 or 2% of the light will be used, and 2) the light will not be even. You could probably even it out with some diffusion material behind the slide, but then you lose more light.

What you would want to do with your system is probably to build in a "condenser system" behind the "slide." This would essentially be a lens system that projects an image of the light source into the aperture of the projection lens (note that any light NOT entering that aperture is lost). This will automatically even out the light as well as greatly increase collection efficiency. As a rough guess you might get 10 or 15% of the light.

So the slide projector is starting to sound pretty good, huh?

I'll be glad to explain further, or kibitz on your design should you want to go that way.

AgX · Nov 4, 2018

With a slide projector one also could mount a vignette within a slide to give the beam a specifc shape. Also at least over here there are some cheap sliding stage projectors with mains driven lamps. These thus lack the heavy transformer and any motorized slides changing mechanism.

David Brown · Nov 4, 2018

Mr Bill said:
You mentioned using a slide projector, but mounting it, etc., is a problem. Well, I would go along with AgX; it's easier to build a mounting fixture for the slide projector than to rig up your own projector. If necessary, pull the guts out and remount on your own baseplate, or whatever...

Mr Bill: Thanks for this. Exactly what I was hoping to hear about. I think you and AgX are correct, though, in that a slide projector is still going to be the best bet. As I said, i have a mount, but it's for basically horizontal use only. I'm going to consider fabricating a mount that will allow me to tilt up to say, 30 degrees. That should be more than enough for what I have in mind - definitely not directly over head!

I have two Kodak Carousels, and I will be willing to sacrifice the lesser of them. They are so heavy! But most projectors are. Still, if Brett Weston could mount an 11x14 view camera to point at the ground, I can do this, too!

MattKing · Nov 4, 2018

You could mount the projector level, and use a mirror to angle the light where you wish.
Maybe a Lensbaby would work too.

darkroommike · Nov 4, 2018

By watching Ebay and haunting camera swap meets I have acquired three Photogenic Mini Spots, these units use a glass Fresnel, Couple that with a wee tiny snoot and the light is pretty directional. I never give more than $30 to $0 USD for one.

AgX · Nov 4, 2018

David Brown said:
I'm going to consider fabricating a mount that will allow me to tilt up to say, 30 degrees. That should be more than enough for what I have in mind - definitely not directly over head!

Make arrests at the table for the feet of the projector or its casing and then strap it down to that board.

Chan Tran · Nov 4, 2018

I use the slide projector without the lens. The slide project has condenser lenses to narrow the beam before hitting the slide. A 35mm projector only need to illuminate a 36x36mm area. Most Kodak carrousel has tripod socket.

Mr Bill · Nov 4, 2018

darkroommike said:
By watching Ebay and haunting camera swap meets I have acquired three Photogenic Mini Spots, these units use a glass Fresnel, Couple that with a wee tiny snoot and the light is pretty directional. I never give more than $30 to $0 USD for one.

Another option in the used equipment market would be a Norman Tri-Lite. This is a bonafide projector, using a condenser assembly and, as I recall, a slide projector lens on the front. There is a slot to insert a slide, or whatever. The last model made could use up to 2,000 Ws as I recall. The Tri-Lite was essentially a light head, you would also need a Norman flash pack to operate it. They also contained a modeling lamp, so you could see what you were doing. This unit has the advantage of being usable with either the tungsten modeling lamp or the flashtube, to match color balance of whatever other light you are using.

I don't recall when the Tri-Lite went out of production, but I don't think it was made after Norman's long time owner, PhotoControl of Minneapolis, went out of business. (Norman was acquired by another company after that, but I think they only kept on with the more profitable gear.)

Something else perhaps worth mentioning is that photo enlargers with condensers are essentially the same sort of projector (although much more difficult to mount).

samcomet · Nov 4, 2018

MattKing said:
You could mount the projector level, and use a mirror to angle the light where you wish.
Maybe a Lensbaby would work too.

+1 Many years ago before the advent of LED lighting I had to light a small set (miniature) of a jungle setting for a scene in a film. The cameraman and I came up with the idea of using one Brute Arc (225 amp DC carbon arc) mounted a fair way away from the set aimed into a "jungle mirror" which was a 5 x 5 array of 1 foot mirrors mounted onto a frame. Each mirror could be individually adjusted with pan and tilt. The array was above the set and the net effect was individual beams of light coming from seemingly the same source but at varying angles as if it was the sun shining through a dense jungle canopy. Scaled down this might be an idea worth considering ala Matt King's post.
cheers and good luck,
Sam

AgX · Nov 4, 2018

Chan Tran said:
A 35mm projector only need to illuminate a 36x36mm area. Most Kodak carrousel has tripod socket.

-) some projectors illuminate up to 40x40mm (Super-Slide)
-) German Kodak Carousel projectors got no tripod socket, they are on the most heavy side anyway.

David Brown · Nov 4, 2018

AgX said:
-) some projectors illuminate up to 40x40mm (Super-Slide)

They all do. The circle of illumination has to cover in excess of 36mm, so that slides can be shown both vertical and horizontal. I suspect that it is at least 40mm, if not more.

-)

AgX said:
German Kodak Carousel projectors got no tripod socket, they are on the most heavy side anyway.

Neither do either of mine. Let's face it, a built in tripod socket would have solved all of the problems from the get go.

David Brown · Nov 4, 2018

Well, there's this: https://www.ebay.com/itm/MOLE-RICHA...m=332857809383&_trksid=p2047675.c100011.m1850

AgX · Nov 4, 2018

David Brown said:
They all do. The circle of illumination has to cover in excess of 36mm, so that slides can be shown both vertical and horizontal. I suspect that it is at least 40mm, if not more.

Actually not all european models illuminate 40x40mm.
Some not at all, some at condenser modification, some from the start.

That for illuminating a 24x36mm slide the illumiation circle at least must be 43mm in diamerter is obvious, but for 40x40 that need to much bigger.

samcomet · Nov 4, 2018

David Brown said:
Well, there's this: https://www.ebay.com/itm/MOLE-RICHARDSON-TYPE-280108-FOCAL-SPOT/332857809383?_trkparms=aid=222007&algo=SIC.MBE&ao=2&asc=20140602152332&meid=326a4b8c930e48be9e1797e26356ef6e&pid=100011&rk=6&rkt=12&sd=312278066700&itm=332857809383&_trksid=p2047675.c100011.m1850

David,
Yes that would work but you might need the Mole Richardson Mini Mole lamp to start with as well. That appears to be just the condenser lens. Condenser lenses are designed for the fixture and come in various focal lengths for a particular "throw" i.e. distance from lamp to subject. Follow spots are typically long throw to get from the rigging to the stage floor, but these Mole lenses are usually short throw for table top work. They do also have a longer throw lens but it also does work for table top as well. If you do go down this path, you would need to remove the fresnel lens from the lamp fixture and replace it with the condenser. The M/R lenses are focusable and have internal shutters for shaping the light output. Maybe you might want to look for a small short throw theatrical fixture (i.e Leko's or ellipsoidal) which also focus and have shutters but with the added ability to insert a gobo. A gobo is a strip of metal with a pattern cut into it that throws the pattern onto the subject; typically clouds, or stars or rain patterns. I used to make my own for whatever purpose by drilling and cutting thin bits aluminium sheet. They are also available from the usual lighting houses pre laser cut into myriads of patterns. If you end up wanting to use a gobo you would also be in need of a gobo holder. This is what the Mole plus lens would look like:

https://www.ebay.com/itm/Mole-Richa...itm=322797740610&_trksid=p2047675.c100623.m-1

This is what a gobo holder looks like:

https://www.ebay.com/itm/Mole-Richa...itm=323524985564&_trksid=p2047675.c100623.m-1

The gobo holder is for a much larger lamp than the Mini Mole. Also the Mini Mole with the lens in my first link has a user added mask at the front of the condenser - it's not normally part of the product.

I do really hope this may help,
good luck and cheers,
Sam

darkroommike · Nov 8, 2018

Mr Bill said:
Another option in the used equipment market would be a Norman Tri-Lite. This is a bonafide projector, using a condenser assembly and, as I recall, a slide projector lens on the front. There is a slot to insert a slide, or whatever. The last model made could use up to 2,000 Ws as I recall. The Tri-Lite was essentially a light head, you would also need a Norman flash pack to operate it. They also contained a modeling lamp, so you could see what you were doing. This unit has the advantage of being usable with either the tungsten modeling lamp or the flashtube, to match color balance of whatever other light you are using.

I don't recall when the Tri-Lite went out of production, but I don't think it was made after Norman's long time owner, PhotoControl of Minneapolis, went out of business. (Norman was acquired by another company after that, but I think they only kept on with the more profitable gear.)

Something else perhaps worth mentioning is that photo enlargers with condensers are essentially the same sort of projector (although much more difficult to mount).

I have played with the Tri-lite and it is basically a slide projector with a Norman Flash tube. It can also be be rewired to use on a Speedotron Black Line power supply, so any used ones you can find need to be checked out professionalle. Black line and Norman use the same connector but the pinout is different. Norman makes another, really big, Fresnel unit, can use with the metal projector scrims used in theatrical spots. And years ago my boss had a DIY one adapted to a Photogenic monolight, made of wood, that also used those scrims and a plastic Fresnel like is used those full page magnifiers.

M Carter · Nov 21, 2018

I've found Leko lights - theatrical spotlights with a very tight beam - for $75 or so. They'll take a 1K or 575 bulb, and you can put gobos in them to control the size of the beam. You can get very distinct, pencil-light beams from them, and they have standard yokes and 5/8 mounting hardware and gel frame holders.

Many folks have mentioned fresnels, but those are nothing like the light from a slide projector or a Leko, which is much more distinct and hard-edged. if the OP wants a projector-style light, he'll need a projection-style lens, not a fresnel which has its own look.

Source 4 makes a mini-Leko which will rest in the palm of your hand - $300+ though. If you shop around you'll find lights for retail jewelry display that have focused lenses like a Leko, may be an option as well.

David Brown · Jan 8, 2019

UPDATE:

darkroommike said:
By watching Ebay and haunting camera swap meets I have acquired three Photogenic Mini Spots, these units use a glass Fresnel, Couple that with a wee tiny snoot and the light is pretty directional. I never give more than $30 to $0 USD for one.

I have three of these as well. Not long after starting this thread, I found a "Focal Spot Projector Lens" for a different light on eBay. The seller had a picture with a ruler showing that the mount was exactly 4 inches. The Photogenics are "nominally" 4 inches, so I took a chance. (The snoots for the Photogenics are 3 7/8" in actual diameter) Anyway, all I had to do was "adjust" the mounting lips a wee bit and it fit. Not as hard edged as I'd like, but will still be useful. It also has adjustable blades (like shutter blades) that can narrow the beam a good bit, but they make a square edged beam. I may get some thin sheet metal and experiment with some round holes in their place.

PS: Haven't given up on using the slide projector for some things.

Adapting a projection lens to a studio light

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