CDMH Lights

3rd November 2004

Just ran across these on the DeSisti site Ceramic Metal Discharge Halide.

Anyone used these? They promise the equivalent of 1000watt tungsten from a 150 watt fresnel fixture. It's not fluorescent, and it's a lot cheaper than HMI.

http://www.desisti.it/Country/usa/lighting/product-type.asp?IDCategoria=6

Anyone used these?

I'm thinking of using them in a small studio. Here in Arizona summertime, saving energy pays off double in the AC bill. But I'm wondering what they're like for color rendering etc. I don't mind that they're 3000* K.

Steven Bradford DP/Instructor
Collins College
Phoenix AZ

I have seen such a unit by K5600. The bulb could get into a standard HMI head but a different ballast is used. I was not expecting to see it, so I carried no colourmeter. By eye I would say the light is close to 3200 but not quite on it - just as is the case with fluoro's, but in a different direction.

I hope it helps

Argyris THeos
DoP
Athens Greece

Argyris Theos writes :

>By eye I would say the light is close to 3200 but not quite on it - just as is >the case with fluoro's, but in a different direction.

Yes, that would make sense. Frankly I'm always shooting video slightly warm, so it would be a plus to have a 3000* light on a video stage. Save money on Gels.

Steven Bradford
Phoenix Arizona

>Just ran across these on the DeSisti site Ceramic Metal Discharge >Halide.

>Anyone used these? They promise the equivalent of 1000watt >tungsten from a 150 watt fresnel fixture.

Steven,

Exploring that link you give reveals a few points :

>- COLD restrike only,

>- DMX on/off optional - suggests these are not capable of being electrically dimmed.

>- Suitable lamp types "150/830" [3,000k] and "150/942" [4,200]. I'm guessing that this suggests the 3k lamps are lower CRI than the 4.2k?

Anyway you look at it, its the CRI of the bubble that will determine how suitable these lights are for your studio. I suggest you try and source data from the likely lamp manufacturers - Osram, GE, Philips...before you go too far.

15% power consumption [c/w a 1kW tungsten] sure is a saving on the power bill...

Cheers,

Clive Woodward,
Perth, Western Australia.

DeSisti have been using CDM type ceramic globes in their lamps for a while. I first saw one used in a Pup (1000watt)I thought it looked a bit green but the colour temperature meter said it was OK. Phillips make a 150w/830 (3000K) that will fit a Blondie, same size as a (240volt)FEX. It requires a ballast like the Osram Powertronic PTU 150 to power it.

Other than the obvious power saving they also run cold... no high infra- red output so not much heat. We were thinking about using them in space lights, low power consumption and very little heat produced from a six kilowatt light. There is however a significant re-strike time, much the same as a HMI Par, which can be a real drag. The manufacturers assure me they are working on lowering the re-strike time.

Graham Rutherford
Gaffer
Australia