Cinematography Mailing List - CML

 

Search

Homemade Ringlight

Published : 4th December 2006

I want to make a ringlight for use in music videos - I have one next week so want to make it ASAP - I have been looking into making it out of LED's and have hit a snag - I am looking at white 5mm LED's from Maplins (www.maplin.co.uk) N21BY and N29AT - I have noticed on the spec sheet it states "The LED light output is strong enough to injure human eyes" - and obviously don't want to be injuring my artist! - The ringlight will be placed around the lens and the artist will be about 5ft away - would covering the LED's with diffusion help?

Are there LED's that I could buy that would be safe to make a ringlight out of? Should I be trying to make a ringlight out of a different type of light? If so what type of light?

Anna Carrington
AC & sometimes DOP
UK


Anna Carrington wrote :

class="style15">> I want to make a ringlight for use in music videos

First off, the statement: "The LED light output is strong enough to injure human eyes" may not be literally true except under extraordinary circumstances, but may be a legal disclaimer in order for the manufacturer to disavow liability in the event of injury, like the notice on shampoo bottles -- "not for internal use." or it may just be a sales ploy.

Second, re-inventing something that already exists can be expensive in terms of both time and money. Renting something like a Kamio may be far cheaper in the long run.

class="style15">>>The ringlight will be placed around the lens and the artist will be >>about 5ft away - would covering the LED's with diffusion help?

Yes.

class="style15">>> Are there LED's that I could buy that would be safe to make a ringlight >>out of?

There are hundreds of choices.

class="style15">>> Should I be trying to make a ringlight out of a different type of light? If >>so what type of light?

You don't say if you're looking for a battery powered unit or not, but if line powered is ok, and if you're looking for something fast and cheap, I recommend the humble circular fluorescent ceiling fixture.

All you have to do is reposition the ballast and cut a hole in the center of it, ala KinoFlo's Kamio.

Brian Heller
IA 600 DP


Brian Heller wrote:

>if you're looking for something fast and cheap, I recommend the >humble circular fluorescent ceiling fixture

I second the esteemed Mr. Heller here.

If you are using a lot of LED's at full brightness, you need to use special metal-clad PC boards that act as heat sinks, as LED’s can put out quite a bit of heat. Note also that "white" LED’s can be pretty deficient in terms of spectrum -- their CRI can be pretty low, because they are usually a Blue LED with some phosphors added to the mix (though this is changing).

Where LED’s are coolest is in RGB fixtures, which are completely controllable in terms of colour of light. You can find fairly cheap LED DMX-controllable lamps on eBay, and you could put a few in a circle.

I'm a big fan of LED’s, and we use them in our film scanner, but there are some tricks to master in terms of driving them properly.

That said, there are dirt-cheap LED flashlights with 12 or 24 LED’s, "white" -- that can be had very cheaply (I got one for $.02 on eBay, though the "shipping" fee was $12 -- a few of those in a circle with some diffusion material would do in a pinch. The one I got was a "headlight" -- 2 AA batteries and a strap to go on your head. Not bad, though quite blue.

Jeff "prefers the darkness, but candles are ok" Kreines


class="style15">>I want to make a ringlight for use in music videos - I have one next week >so want to make it ASAP

In my opinion you do not have enough time to experiment with LED’s.

Quick and dirty (You will have to check colour temp). Rope lights and Christmas light strings. Both require AC but the amps drawn are minimal making it fairly easy to use a inexpensive inverter with a battery pack or a auto/marine deep cycle battery on remote locations.

A coat hanger wire is stiff and works well for making a doughnut for the lights fast. A little forethought and you can bend it in such a way to use the rods for mounting.

Quickest :

The rope lights are nice because you do not have exposed lamps. I have used this for a few interviews with several sheets of Opal pre cut and standing by to control the look.

http://www.christmaslightsetc.com/rope-light.asp

Second Quickest :

Miniature bulb Christmas string lights can be wrapped around a coat hanger wire but be careful in case it heats up. Also check to be SAFE. There can be no frayed or exposed wire attached to the camera. So a wire must either have shrink wrap cover or INSPECT INSPECT INSPECT!

The grips can make a sturdy ring using spray 77, and 3-5 layers of B/W foam core. Then you can punch or drill holes to push the lamps through which ever side (black or white) that works for your application. This gives the ring a clean look to set. You can get clever and add one or more layers of blackwrap. The blackwrap (there is also whitewrap for reflectance) is first glued (spray 77) to the set side. A second piece of blackwrap is cut with "extra" on the edges (Hole and outer edge) and glued. The extra blackwrap is used to pinch the gel in place, just like a edge on a aluminium roasting pan.

The Christmas light strings are in my opinion better then the rope lights. I have used the miniature light strings for a more sparkling kind of eye light. You have to be a little careful, a shot that is too Close up the talent's iris can get too busy. that is not the best way to describe what I mean but once you see it you will know exactly what it does to different eye colour and iris. One ring I made on the fly used two 50' (fifty foot) strings (approx 200 lites). I put both on separate dimmers. For the lighter skinned actress, one string was perfect. The darker skinned actor was lit with both strings but not at 100% intensity. The lights are a warm colour temp already, dimming gave caramel colour skin tone a nice subtle boost. Again my description will be better understood at a camera test or on set. ONE WORD OF WARNING all strings ARE NOT EQUAL. Some can lose one bulb and remain lit. Other strings are designed to go dark when one miniature bulb B/O (Burnout).

http://www.christmaslightsetc.com/categorydetail.asp?CategoryID=533

I own two old Christmas light strings. The bulb size that is used in this string is called a "C-shape".

http://www.bulbs.com/products/product.asp?page=products&class=656

You can make a more professional looking ring with various base configurations/manufacturers. ( http://tinyurl.com/op9uj )


You can screw and unscrew bulbs to alter the look & intensity, or use a dimmer for intensity only. Again you will have to CHECK your colour temp.

I read another post recently and will practice this tip on my next job ... that tip ... burn your bulbs for a least a half hour before you use them on set. Have all your spares pre burned as well. This reduces the chance of colour shift between takes.

D P Shannon
Gaffer/Rigging Gaffer
United States


What about this?

http://www.clouddome.com/specs/led.html

Jessica Gallant
Los Angeles based Director of Photography
West Coast Systems Administrator, Cinematography Mailing List
https://cinematography.net


All this LED discussion is quite interesting. I tried to post a message about 6 months ago asking about any experience with Zylight. The moderator caught it, I asked if it sounded a bit like an ad for that company and he said "bingo," and then, after a short discussion, said "okay, go ahead and post." I moved onto other things and didn't bother to repost.

Zylight sounds like a wonderful little product, 50 LED’s in a little cube, switchable 3600k or 5200k, even able to project every colour of the rainbow. I saw two problems: One, it took three of them to equal the output of a thousand watt tungsten bulb and (2)--and much more importantly--the damn things are close to a $1,000 each--about 20 times what you should be able to design and produce yourself and about 10 times what the retail value seemed to be.

Are LED’s the wave of the future? They're obviously a long way (at this point) from being able to light up the night but I keep thinking, man, if I knew what I was doing I could create an extremely versatile, relatively cool, daylight corrected, low power consumption studio light for less than $50. Maybe a diffusion screen of some sort, maybe multi-lens, I don't know.

Obviously there a people on here that know the technology better than I.

I would love to here from them.

Denny Williams


Anna,

I have to say you are trying to re-invent the wheel without the time, and possibly the level of expertise to do so.

Homemade ringlights have been the sport of photographers and cinematographers as far back as the 1940s, when Clifford Coffin, borrowed the technique from dental photographers and applied it to fashion photography. Numerous amateur and commercial variations have appeared since then including the Garland light for use with Vista Vision cameras in the 1950s, Nikon flash rings in the 1960s and more recently the popular Joe Dyer ringlight using a ring of low voltage halogens in the 1990s, before the advantages of LED’s and the quality of the core technology made them feasible in the last couple of years.

Your biggest problem to solve is lack of time, but aside from that let’s look at the particular issues with regard to LED’s.

You can’t merely go out to Maplins and buy a random bunch of white LED’s, if you are even moderately interested in colour temperature or in the case of LED’s (CCT) and colour rendering index.

We select our LED’s from one or two bins out of a possible 30 or 40 combinations, optimising colour quality, lumens per watt, forward voltage. Buying in small quantities is unlikely to allow this selection process and quality control.

Secondly LED’s have to be driven properly. You cannot simply attach a battery to them without current limiting protection. You need to understand how to design a buck or boost topology driver for your array, depending on the input voltage and if you want to cover the wide range of voltages around on a film and television set, at least between 11V – 36V, and the forward voltage of your array, the driver may need to seamlessly switch mode, without effecting the output as battery voltage falls. To allow dimming without colour shift, you’d need to use one of a variety of electronic control methods available. Pulse width modulation is the most commonly used by a variety of manufacturers, and a well known basic electronic control technique. This is not a simple job by any means, and our team spent nearly five months designing our Version II ballast to solve the problems in an efficient way. There are off the shelf solutions, but they won’t necessarily work efficiently with your array.

Thirdly you have to address thermal management issues to maintain the quality and output of the LED’s over time. Whatever you may hear, LED’s aren’t 100% efficient, or heat free, and therefore there is a lot of heat to dump somewhere. If you don’t want the lamp to end up the size of Gibraltar, then this isn’t easy either.

Fourthly your fixture needs to be usable, and practical, and allow easy mounting to a variety of cameras and lenses. Again we took months optimising our design to work with the widest range of commonly used camera and lens combinations, and none of the commercially available solutions that I know, will work with every camera and lens combination in the market.

Finally, and I wouldn’t deter anyone from making their own custom lights for particular problems, it will cost you a lot more time and effort than you will ever anticipate. You can probably multiply your expectations by a hundredfold. As a professional your time has a value or cost that must be factored in.

There are a wide range of commercially produced products, available for purchase or rental, and I would seriously consider renting one for this shoot. At least they will have been well used and tested and their inherent limitations clear.

In the LED market, products from amongst others

Gekko Technology
CineLed
Litepanels

If you want to go the florescent route, the excellent Kamio from KinoFlo.

I am very biased in favour of kisslite, but all have some beneficial aspect or feature and all are widely available in London from -

Cirro Lite
AFM Lighting
ARRI Media
Cruet
Direct Lighting
Heavy Pencil
Visual Impact 24/7 Dept

Oh and I must declare my interest. I’m the designer of kisslite and the MD of Gekko Technology.

Regards

David Amphlett


I've made some out of Puck lights. Nice thing is you can run it on 12volt or 120

BILL BERNER
ICG 600 DP


You know, that seemed very like an ad for kisslight which of course is not allowed under CML rules.

You know I love the kisslight David but stick to the rules.

Oh and the Robert Palmer promos from the mid 80's were shot with a ringlight made up of self mirrored photofloods.

--

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


Geoff said :

class="style15">>>Oh and the Robert Palmer promos from the mid 80's were shot with a >>ring-light made up of self-mirrored photofloods.

How big in diameter was this ring-light?

Cheers,
Jeff Barklage, s.o.c.
US based DP
www.barklage.com
view reel online : http://www.watchreels.com/jeffbarklage


class="style15">>>I want to make a ringlight for use in music videos

Check out Gekko Technology and the kiss lite

http://www.gekkotechnology.com/

These lights are available to hire and the LED’s are colour corrected, although I’m not sure if this is within your budget it is a light that has been professionally designed and engineered by a Lighting Cameraman DOP Dave Amphlett to be used as a ring light

ATB
&
Kind Regards

Andy Leonard
Lighting Cameraman.


class="style15">>How big in diameter was this ring-light?

Big

About 3 feet across.

Great diffusion from the heat haze

--

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net


Thanks to everybody that has given me advice on building a home-made ringlight.

I have to admit that I had a secret weapon in my "home-made ringlight" plan - e.g. my father who had offered his services to help me build it and a Gaffer friend who had given us some tips - but we have put the LED project on hold for a while - instead I am going to experiment with Christmas lights and a close-up inspection lamp which once you take out the magnifying glass looks suspiciously like a fluorescent ring light! - I might even get a real ring-light to play with as our budget has been relaxed thanks to Kodak who have generously donated some stock to the project!

Anna Carrington
AC
UK



Sponsored by

 

 

 

 

 

 

 

CML Home CML-Tests Home

© copyright CML - Cinematography Mailing List all rights reserved