retail MH fixtures for video/ greenscreen work
 

I picked up about 40 of these track light fixtures from a local retail store that was going under. http://www.amerlux.com/download/590_...l_wash_ltg.pdf

We're going to use them in our own little retail store, but I'll likely have several left over and am contemplating using them somehow in my studio downstairs. I'm setting up a permanent greenscreen rather than the portable one I usually use to shoot full-body static stuff for the web.

The bulbs in the fixtures are 100w, 3k temp [spec. #MHC100/U/M/3K/ALTO]. I looked up the specs and they're supposedly a 85 CRI. For lumens, it ranges between 9000 & 7000, and I could maybe shine them though a softbox or something. I'm also concerned about UV radiation, but the glass over the fixtures hopefully blocks most of it. My studio will have pipe overhead and I can make the necessary changes to put a c-clamp and plug on each one. They're a bit heavy and unwieldy for any kind of field work. I use a combination of CFLs and Omnis for that.

Considering I paid less than $10/each for the fixtures (really), they're a fantastic bargain for the store. I've already put a few online on the sales floor... and man are they bright for a 100w bulb, and the light seems nice to my eye. I'm just curious on anyone's thoughts on using 'em for video.

Thanks in advance,
Brian Brown
BrownCow Productions

Metal halide at that price is a great find. You probably don't have any UV worries as most of those bulbs these days of 150w and less have an outer glass uv protection jacket that blocks most of it and if not, its most likely that the glass on the front of the fixture will block whatever is left with some kind of built-in filtering. On the chance that they didn't build anything like that in, the only way to know for sure would be to buy a UV meter (or two). But, that's a whole other story and complicated in itself to get the right one that detects A, B and C bands of UV radiation. Failing all that, you can just get a uv filter gel (Rosco Cinegel 3114 Tough UV Filter).

Thanks for the info, Richard. I think I'll go ahead and bootstrap something together.

I still have the issue of potential buzzing from the magnetic ballasts, but I'll run some tests. I'll also probably need to run tests on a color chart to compare the real world differences between my MH fixtures and traditional tungsten, esp. on flesh tones.

Regards,
Brian Brown

If they're magnetic ballasts you'll most likely have some flickering at higher shutter speeds and frame rates so some experimentation will tell you what you can get away with. As for color rendering, the Macbeth color chart is definitely a must, but one thing I've found is that its still good to take some pictures of real people under the light just to see whether its flattering or not.