Cool Lights CDM (Ceramic Discharge Metalhalide) vs LED

[Tom Wilkinson]

I'm new to video so I don't have any current lights. My first attempt is to set up a lighting kit for interviews. I have read a book on video lighting and I have watched a DVD on interview lighting but I have no practical experience, and that's why I need your input. I like LED's because they are light and are low power. I like CDM because they are hard lights. You can make hard lights softer but you can't make soft lights harder. LED's are a bunch of hard lights that don't look right without diffusion or bounce. It looks like the CDM lights are bigger and heavier.

LED Kit
One CL-LED600 600 LED Panel Spot [Key]
One CL-SPSB600 LED 600 Speed Softbox Kit
Two CL-LED256 256 LED Spot [Fill, Back]
Two CL-SPSB256 LED 256 Speed Softbox Kit
One CL-MF0070 Cool Lights CDM 70 Fresnel [Background]
One CL-SCR0300 300w Scrim Set

CDM Kit
One CL-MF0150 Cool Lights CDM 150 Fresnel [Key]
One Cool Lights CL-SRB0650 Fresnel Softbox Kit
Three CL-MF0070 Cool Lights CDM 70 Fresnel [Fill, Back, Background]
Three CL-SCR0300 300w Scrim Set

It seems that most people on the forum talk about the Cool Lights LED lights but few people talk about the CDM lights. Please provide comments based on your practical experience with these lights in an interview setting.

Thanks
Tom

[Andrew Dean]

i've got a whole truck of cool lights. cdms, led, hmi...

People talk about "interviews" like its a fixed setup. I mean, you can have interviews with that totally fake 2020 look or a very natural light setup in a bright space... or grungy or moody or outdoors at mid-day.

I mostly shoot dramatic stuff, but have been called on to do my share of interview lighting too.

My personal preference is to find a space with attractive natural light/background and embellish it. That usually means the led panels because i can dial in fill to exactly what i want. Sometimes i put some diffusion on the barn doors, but as fill i generally just use them bare. If shooting on dslr I will always try to find a way to punch one of the cdm 150s as a hair/rim light. I personally don't care if it is a bit hot. I like the way dslr handle an overexposed rim. If i had a cdm 70, i'd probably try that first though, just to have a tad more control.

If i'm mobile on a "pack and go" interview, i'll just bring a pair of LEDs and find a window to help out.

If its night or if there isnt anything attractive light-wise, i'll pack in lights. Whether its leds or cdm depends on the size of the room. A tiny office, even a cdm 70 will be a lot. A big board room and the 150s are just about right. The LEDs have a lot of punch, but even the "spot" is a pretty broad beam. Its hard to light up a subject in a wide shot without filling up the rest of the room. Much easier to do that with a fresnel.

So it sounds glib, but if i had to choose between LED OR CDM, I'd base it first on the size of the rooms you want to light (relative to the existing ambient light) and second on portability. For really big spaces, you really need grunt, and the LEDs fall off too quickly/quirkily for big rooms. For really tight spaces, the fresnel HMI can easily be overkill.

I don't have any examples handy of my cdms used for interviews. But i pulled some stills from a crazy interview piece i did awhile back. We shot like 8 different interviews in one day at 8 different locations. We'd show up and I'd have at best 10 minutes to find a spot, set up two cameras and do whatever lighting i'm gonna do. (to save time i'd shoot a wide and tight angle at the same time). Then we'd have maybe 5-10 minutes to pack down and leave (me carrying most of my gear) so i had to really hone down my kit for that.

My full light kit was two LEDs, two compact stands and 2 extension cords. Out in the car i had a pair of batteries "just in case". The most important light i had was window light, which i would run around frantically until i found a spot with interesting light or background. Here are some of the various locations. (this is a FYI of how i worked with just the led kit, not me trying to imply these are super awesome lighting examples)

Please note, these are jpegs made from a "email quality" mp4. The full HD files looked way nicer, obviously.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

The mayor had a neat glass office, but it just meant a bright background. I turned on all the office lights and used the 600 spot on the left side behind him a little and up full to approximate light "spilling in" to the office. Then i put the other 600 (flood) on the (camera) right side, just slightly forward, as fill. probably cut it about in half... or i might have just moved it away from him. don't remember. This was the most rushed setup i had with closer to 8 minutes from walking in the door to starting the interviews.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

I'm not terribly happy about the two light sources in his eyes, but overall i think it turned out decent. I'm very pleased with the "light and airy" attitude i was able to achieve this whole day. I get really tired of people sitting in dim caves to be interviewed.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

This was a panic, as it started to rain. It was really overcast and cloudy, so all i did was put one of the leds to the right and back a bit up full with a folded sheet of "spun" diffusion pinned to the doors. It just added a tad of directionality. I picked a location where the background was interesting and a tiny bit in shade so the subject could "pop". Again, nothing magic, but serviceable for no time. As we were on a pier, i ran the LED off battery.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

The room we were to shoot in was unavailable, so i grabbed this tiny closet of an office. (the wall is like 2 feet from her head). It had a window so i put an led to simulate/embellish the natural light. I put it high and aimed down so it wouldn't light up the background much. I might have put some spun on it, but cant remember. I grabbed a potted plant from across the hallway and shoved it into the the office. The room was shaped like a wedge, narrowing to a point behind her. I put the seam of the corner behind her and shoved the plant in to give some depth. While i was rigging the camera i had somebody bring their company logo on the screen on the wall, but it wasn't very visible in the tight shot... which i mostly went with.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

had a big window so i used it as key and put an led on the left side as fill. (its the sole source of light on the left). I used the curtains to mask off light from the wall behind and found a big orange banner thing that i poked into the background.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

I had these interesting patterns on the windows of the office, but no light on them. I needed one led on the right to fill in the face, so the other one i put halfway in the doorway with one side hitting the camera left side of the guy's head, and the rest trailing along the pattern on the windows. I really could have used a 3rd fixture to get this right.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

Tough location. A dark moody bar. I turned up the house lights all the way, then put a led to camera left as key, used a window as fill, then put a led outside a glass door to the back right in order to give some rim. It wasn't enough, and he kinda flows into the background, but its something. The key i put a few half sheets of cto and the rim i put one sheet of 1/4 cto, just to try to bring it closer to the tungsten sources. I'm not happy with the rim angle or the separation of the suit... but its a black suit in a black bar... so i did what i could.

http://www.dvinfo.net/forum/attachme...1&d=1294198407

Radio stations arent really known for lighting. Thats a led on the right with some spun on it, i think up full. I turned on all the lights of a kitchen to the right too so it offered a little help. I put a led dialed down a bit to the left. She had pale skin and a black dress. I didn't have enough power or space to shape her dress, so i put her in front of a lighter background so he has separation by way of contrast.


And thats a days work with a pair of cool light LEDs. By themselves I would have been pulling hair, but using natural sources as well, they did a serviceable job. They are remarkably versatile in this setting, not to mention super light and portable. If i was lighting from a dark room, i'd rather have a pair of cdms though. A cdm rim with a white card bounce for key gets you a whole lot of action for not much effort. Then you can concentrate on dressing/lighting the background.

Feel free to comment or ask anything. Again, i'm not at all setting these up as some reference point for lighting. In somebody else's hands everything could have been much different/better/worse. As i was the lighting and camera guy, as well as directing the interviews... it is what it is.

Cheers, and hope that kinda sorta helps your search.
-a

[Garrett Low]

Hi Tom,

Most of the time I don't need to provide lights so I only have a very minimal lighting kit. It consists of 4 CDM 150's, 1 CDM 70 and a Comer 1800 LED on camera light. I have had to do interviews in a variety of settings with just the CDM lights and they have all turned out to the satisfaction of the director. I've also shot dramas with just the CDM's. Of course these were in smaller locations. I've also got two of the softboxes and I usually use at least one of them when shooting an interview (but not always).

I also always have a number of scrims, a small compliment of gels, and several flags and bounce boards on had at all times. That's one thing that most people starting out with lighting seem to fall way short on. You can do a lot with a minimal number of lighting instruments and the right gip kit.

The CDM's are actually lighter than the LED panels and I like the ability to focus them. They do give off more heat than the LED's or FLO's but they're a lot cooler than the tungsten lights and my interview subjects really appreciate that. The biggest disadvantage I've found with the CDM's are that you can't use a dimmer on them. That's why I carry a bag of scrims bit it would be nice to be able to just throw a dimmer on them.

Other than that I've gotten some really nice looking interviews with them.

-Garrett

[Richard Andrewski]

The reason that people mostly talk about LEDs now is its the new hot thing. If someone is starting from scratch they are thinking about what is the sexiest, most compact light they can get right now.

You can do probably about 80% with LEDs that you can do with a fresnel. That is, for most common uses of flooding an area with light and some minimal control, the LEDs are fine. The other 20%, namely those things that require normal "shadow" behavior, call for a traditional instrument like the CDM or tungsten fresnels.

So you have people that need that traditional behavior for everything and you have others that don't care for the most part. For example, someone who would be prone to using a fluorescent kit for most everything they do, probably would also be a candidate for LEDs. The behavior of the shadows from fluorescent and LEDs are about the same--pretty undefined.

The person that is more likely to not use fluorescent or softlight for most things they do will probably prefer the control afforded by a fresnel and not choose LEDs except for things like back / hair / rim / accent lighting. Like what Garret said about using the small LED unit for accent lighting.

[Michael Panfeld]

I'd keep my kit to a minimum right now. There are several developments in lighting that have just started coming to market. For example, LEDs with higher CRIs are here, and prices will be falling. There is a new HMI technology called CST that features 3200K tungsten lamps that are hot-strike AND have a much longer useful life and can be switched out with 6000K daylight lamps.

I believe that Phillips invented it. Their 1st lamp is called the Ceramic ST 250 HR. It is the tungsten equivalent to their daylight MSR 250 HR lamp. Same fixture can handle both. Both are hot-restrike. Looks like they also make a 500watt version. Jenbo Lighting International (a Taiwanese manufacturer) has already started making these in 150 watt (6600 hour life) 250 watt (4,000 hour life) and 500 watt (1,000 hour life) versions. Quartzcolor seems to be the first manufacturer with fixtures and ballasts using the Phillips/Jenbo CST lamps that are geared towards filmmaking.

http://www.prismaecat.lighting.phili...mic_ST_int.pdf

CERAMIC FRESNELS

http://lucifer-gmbh.de/produkte_pdf/102105.pdf

Moreover, the prices on LED and HMI fixtures are falling rapidly as competition and production efficiencies are coming into the market.

I like what Garrett and the other posters said about modifying the light with grip gear and about using available lights. A sheet of gel, a metal scrim, set of black or white foamcore boards are all under $10 each. Much cheaper than buying a $400 fixture.

My question to Richard of Coolights is: when are we going to see 250 and 500watt fixtures that can switch between tungsten and daylight?

Cheers

[Richard Andrewski]

Arri has had a "Studio Ceramic" fixture out for over two years now so its not really a new development. They only had the tungsten colored bulb in the beginning as I recall, but later Philips made the 250w HR daylight version in the same socket form factor so you could switch out easily without having to change sockets.

I'm not very interested in the 250w range. We have ballasts for that and could do it but I was more looking in the 400w range for now for any follow on fixtures we'll do in the CDM line.

As for changing between 3000K and 6000K bulbs in one fixture. We've had that capability since late 2007 when we came out with the CDM 150. We have the ceramic 3000K and just about the only quartz 5400K that I know of. Most companies that produce this bulb stop at 4000K as their upper range.

This change out ability hasn't been a big deal though like I thought it would be. Most people prefer to use daylight these days and they only switch to tungsten color when they have to match with other existing fixtures of that color temp. So very few take the tungsten option bulb with mos taking the 5400K one.

[Garrett Low]

Hi Richard,

What is the status of the 400w CDM Fresnel? Some time ago we communicated and you were not sure of when it would be released.

Thanks,
Garrett

[Richard Andrewski]

Hi Garrett,

Just ironing out little kinks in the design still. Maybe sometime early this year if our production schedule will permit.

[Tom Wilkinson]

Andrew,

Thank you very much for your real world examples. It was really helpful that you described the exact setup and provided sample pictures. This helped open up my thinking to include available light.

Garrett,

Thanks for your comments on the CDM lights. Also thanks for mentioning the flags and bounce boards, I have not given them much thought until I read your post.

Richard,

Your comparison of why you would use LED vs. CDM was helpful. I am partial too hard lights but that is probably because of the video production classes I took 40 years ago. I never got into video instead I went into electronics repair then I went in to IT. I am still trying to keep an open mind about LED. I am starting this video hobby now so I will have something interesting to do during retirement in five years. I really appreciate your company making affordable lights, I will be able to acquire both the CDM and the LED lights as time goes on.

Michael,

Good advice, I will be building my light kit slowly, buying only what I can afford because I don't use credit, so I can take advantage of new developments as they come along.

Again thanks all.

Tom

[Scott Brickert]

Andrew,
THANKS for the real world examples and descriptions. Good work under tight scheduling.

I'd vote for sticky status on that post, if there were such a thing as voting... :)