You mean the HPL in the fixture. What do you mean by "dimmed electrically/electonically"? They don't like variacs or they have been corrected for the vibration, your were refering to, in the filament. Or is this just symantics?

No i can't spell, or use Google

You can dim them with any technology you want, it's just a light bulb. We use hundreds of them in our light plots. I think Jaron's point was that you should use a dimmer down at floor level so you don't have to climb a ladder and put some sort of filter on the light. Realize however that the color temperature will change considerably if you dim the lamp.

Jaron, I think the modern theatrical dimmers are pretty good at reducing "lamp sing". This is a new product that I've been hearing good things about for example: http://www.etcconnect.com/product.overview.asp?ID=20041

Actually the household dimmers aren't that bad now either. I just built a couple of in-line dimmers with parts from a big box hardware store (for under $20 a piece) to control 300w arri fresenels. I have not noticed any lamp noise at all.

i agree - i use router speed controls on all my lights and they work beautifully. But it is a trial and error thing when it comes to lower-end dimmers (like household dimmers or my router speed controls) - some work smoothly and quietly, some don't. The high-end dimmer boards are fantastic, no sing at all in basically any fixture. And yes, HPL lamps are designed to be dimmed, where FRK are not recommended.

I have used lower end boards (both new and old) and they sing like CRAZY on basically any fixture that's not theatrical in nature.

As for variacs - I still have a soft spot for them. When space/weight allows, I love em.

From my experience, creating "sculptural" light with a fog machine is possible but inconvient since the hang time is so short. I rented a hazer for one week, $150 a week, and never went back. Don't even bother with dry ice machines.

Source 4's are great, but I wouldn't say they're the best for shooting on location.
-Alex

People have mentioned a lot of things in this thread, except one important point:

If you want to illuminate a particulate in the air (smoke, water spray, etc), you generally need to backlight it. It doesn't always have to be a true backlight, but the light needs to be more pointing towards the lens than away.

Hey, I said that! ;-)

I think its hear also.

Nate, you explained why more clearly. But you want to light snow from the front.