How much light?

treeman

treeman

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This is more about stage lighting than anything else, but keep with me :)

If you wanted to explain to a stage lighting technician how much light you needed to get a good enough exposure, is there a universal language that they'd now what you were talking about?

Would they understand if I said I need to be at ISO 3200, f2.8 640th sec?

And also whilst I'm on it if you had 74k watts of light and a photographer said they needed two more stops of light, would that need to be 4 x 74K

Thanks:)
 
Theatre lighting guys talk a different language from us. the light output from the spotlights is normally expressed as lux or lumins, a 650 watt fresnel spot may give out 3000 lumins, this is not a lot of light when its 20 foot away from a stage. in small stages, say schools or villages halls they may have 10K of light. lighting guys will tend to look at the stage rather than get out a light meter. A west end show may have 50k of lights and you will still strugle to get a good shot. rock beands may have 80K, nice.
Theatre togs always use fast lenses f2.00 , its easier now with digital as you can crank up the iso and change the colour balance. years ago on film max tungten colour film speed was iso 160, we all strugled. David
 
I would say "brighter" or "dimmer", it should work. ;)


Realspeed
 
Thanks David, that interesting, I presume they just estimate with experience how big the area they need to light is, and distance of lights to that area.

I just wondered how you'd go about telling a lighting company that you needed x amount of light, i.e enough to get a decent exposure in.

Bazza, thanks, I tried that, he swore and walked off :shrug:
 
treeman said:
I presume they just estimate with experience how big the area they need to light is, and distance of lights to that area.
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No. They just use what is available in the theatre. Usually not enough.

I haven't done any stage lighting for at least twenty years but no one ever talked about any units of light levels.

All you do is see what is available and decide what is going to be used for what function.

I suspect it might be different for high end productions with a budget to hire in whatever they want.

One thing to be aware of with stage lighting - it is very rare to use a light without any sort of filter. The main lights will be fitted with light blue, light pink or straw coloured filters. The pink and straw being used for 'warm' scenes and blue and straw for 'cool' scenes.

This tends to hide defects in costumes, scenery, etc. which show up with plain white light.

flashted said:
a 650 watt fresnel spot may give out 3000 lumins, this is not a lot of light when its 20 foot away from a stage.
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The distance is irrelevant as the spread of light can be adjusted. The level is inversely proportional to the area the light covers. The distance would only be relevant to flood lamps which are not adjustable and they are always close to the stage.


Steve.
 
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Ok for a quick bit of background, I was in the O2 arena last night for the Gaucho Polo, which will be the third year it's been done, and I've covered each one.
The first two years I could get iso 3200 f2.8 at 640th, but last night I was at iso 12800 and struggling to get 400th; so at least two stops less light.

Faster lenses are not an option at 300mm-400mm, so I'm stuck on f2.8, and any less would be too shallow DOF too.

I know all the lights are bought in for the event as there's no house lights as such, and I can speak to the organiser, but I know the first thing he's going to say is "how much light do we need then?"

And if I heard the lighting guy correctly, he said there was 74k watts of lights in there already, but they are up very high on the ceiling.
 
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