tungsten fresnel vs florescent bank question!

[landolando]

Hey there. Here's my question: I'm curious on whether or not there's any visual difference in using a tungsten fresnel or kinoflow/coollights florescent bank, assuming one or the other has been gelled properly to achieve the opposite of their natural affect. For example, if I were trying to get something like daylight through a window, is there a visual difference between a florescent bank or an equally strong (including the half-stop down that happens with gels) gelled tungsten?

Is there a difference between gelling to daylight or having it come out "naturally"?

I am looking for (well, more like "can afford") one (maybe two) more lights to round out a reasonable film lighting kit and trying to decide which I should go with. I already have a 1k strand fresnel and a 300/500 strand fresnel.

Thanks for your help.

 

[cinebuddy]

At base level the flo won't have the throw (that rhymed) of a tungsten unit, so the falloff is much quicker. So lighting through a window from the outside may be difficult. Full CTB knocks a 1k down to like 500w equivalent, throw some diffusion over that and your dropping light pretty quick.

 

[landolando]

Thanks, cinebuddy!


Second question: Is a cool lights cdm is pretty much equivalent to hmi in common use? Is the reason for getting an HMI the same for getting a CDM? That they run cooler, take less watts, duplicate daylight without a gel, or is there another reason? It seems like one could just get a brighter tungsten and gel it to daylight and have the equivalent of HMI other than those benefits.

 

[Cool Lights]

What you said is all pretty much correct, its like an HMI but using a different type bulb from that whole metal halide family of which HMI is a part.

The CDM 150 is about the equivalent of a 650w tungsten fresnel. It only draws 150w to do that and gives a nice daylight, hard light in a fresnel package just as an HMI fresnel would and without gelling and light loss to get daylight. You can't just put a gel on a little bit brighter than 650w fresnel to get it equivalent to a CDM 150. You lose so much light that you almost have to double the tungsten to get the same amount of light. So about a 1000w to 1200w tungsten fresnel behind gel in other words assuming a full CTB.

When you put it that way, the jump from 150w to 1000/1200w to do the same thing is a pretty big deal. Thats why the 150w is worth it and why its such a popular product.

 

[slondon]

What are you trying to accomplish? What are you lighting?

If it's an interior and you have complete control over the lighting, there's no sunlight, maybe just a practical or two, then working in 3200K is perfectly fine, and skin and colors will look great.

If it's an interior with sun coming in, gelling your tungsten heads doesn't leave a lot of light. I'd suggest, though, that you try 1/2 CTB instead of full as to most eyes it mixes with daylight just fine and preserves twice as much light from your lamps so you've got something left to work with that hasn't been absorbed by the gel.

All that said, however, if you're doing medium shots and close up interiors and there's indirect sunlight from the windows, I'd get a 4-bank fluorescent with daylight tubes and use it for key or fill. It's large so inherently soft and the color temperature makes it really easy to work with around diffuse sunlight filtering in from windows that aren't facing south and getting the full brunt of direct sun.

Don't neglect to get a set of tungsten balanced tubes though, because you and your talent are going to like the coolness and look of this light when you are starting with a dark room.

It will soon be a favorite.