Lighting question, please respond ASAP.

aifilmmaker

aifilmmaker

Active member
Are two fluourescent 45 watt 5000k lights bright enough to light a moderately sized room? Are they bright at all?
 
Last edited:
Depends on ISO, f-stop, bounced or direct, color of walls and what "moderate" means.
 
aifilmmaker said:
Are two fluourescent 45 watt 5000k lights bright enough to light a moderately sized room? Are they bright at all?
Click to expand...

I'll say no, but you need to really have more data. 'watts' as usually given by bulb manufacturers has no direct, obvious connection with how much 'light', measured in Lumens. A tungsten 100 W bulb gives off approx. 1700 Lumens, but again, most manufacturers for bulbs 'off the shelf at your local store' may vary considerably.

Then once you have the total Lumen output, you have to consider the shape of the 'beam' of light. Fluorescents are usually housed in a long fixture, and will give off their light in a 180 (approx) degree 'elipsoidish' pattern, and so since there are 2pi steradians in a half-sphere (making it easier...), you can estimate the Lux/fc at various distances.

All this adds up to... it's probably easier for you to set up the tubes, and measure the light directly, at least once, then you'll know for sure whether there's enough.

If this light you are contemplating is a light manufactured by a 'film lighting' company, they should have photometric specifications which list the footcandle/lux values at various distances from the light.

For example, with 100 footcandles (1076 Lux) of light at the subject, one can have a camera setting of f/2.8 @ 1/60 th, with an ISO 100 setting.
 
J's right, you can't really ask for an ASAP response without giving us any info. How fast is your lens? what iso can you shoot at? what iso do you want to shoot at? how big is the room? what color is the room, do you want it slightly under exposed, proper exposure, or slightly over exposed?

Fluorescent usually aren't very bright. I used two two bank kino flos raised up high to simulate real fluorescents for a scene, and we were shooting at about 2.8 (the lens went to 4 so it was one stop down, which I prefer anyways). It really didn't FILL the room with light. That was our intent anyways.

Testing is always your best option as well.

BTW keep in mind if it's regular light fluorescent fixtures there are always problems with color temps and possible flickering.
 
You must log in or register to reply here.
Back
Top