Lighting with Redheads for dummies

[Adrian Sierkowski]

Depends but normally I am using from 300 up to 5000W-- but it all depends. Sometimes I'll be using a 10K if I need to--but I am partial to 1Ks mostly because I am still primarily used to location shooting with 20A breakers.

[Freya Black]

It would be a few cents. Really; the power consumption of such little wattage for a day is barely a blip on a power bill-- especially if you're @240v where the Amps are essentially halved-- though depends what your mains are in your country.

 

Here in the UK, electricity is sold by KiloWatt/Hours not by the amps, although I suspect that drawing greater amps is likely to mean a loss of electricity into heat in the wiring. That doesn't get considered in the usual maths for this tho.

 

It does mean you can draw a lot more from the ordinary household mains at 240v without running into problems tho.

 

Electricity is presently very expensive here in the UK however. I suspect more expensive than it is states wise.

 

Freya

[Brian Drysdale]

Everything from 150watt to 12K. Although usually no bigger than 2.5k when there's no generator. It really depends on the type of lights you're using, LEDs and fluorescents tend to be lower wattage, Most common tungsten units are in the 500watt to 1k range, although 2ks come in handy.

[Vadim Joy]

 

Here in the UK, electricity is sold by KiloWatt/Hours not by the amps, although I suspect that drawing greater amps is likely to mean a loss of electricity into heat in the wiring. That doesn't get considered in the usual maths for this tho.

 

It does mean you can draw a lot more from the ordinary household mains at 240v without running into problems tho.

 

Electricity is presently very expensive here in the UK however. I suspect more expensive than it is states wise.

 

Freya

Just made some calculations, based on 17.7 pence per kWh using 3 lights 800w each for 5 hours continuous shooting it will cost you £2.13 in UK

 

Not that expensive.

[Freya Black]

Just made some calculations, based on 17.7 pence per kWh using 3 lights 800w each for 5 hours continuous shooting it will cost you £2.13 in UK

 

Not that expensive.

 

:) It does add up if you do it over days of course but yes, 3 little 800watt lights are not that big a deal. The average electric heater draws between 1KW to 2KW, so it's nothing that out of the ordinary.

 

I expect that is quite scary to Adrian tho as he was talking about cents, and running your 3 little lights probably works out at something close to $1 an hour!

 

Freya

Edited February 10, 2014 by Freya Black

[Vadim Joy]

If I understood correctly redheads are tungsten (3200 to 3400) lights, in order to make it daylight or HMI (5600) you use ctb, right?

[Vadim Joy]

Just discovered that HMI lights are actually dangerous, they produce UV radiation

[Brian Drysdale]

That's why you can't operate HMis without the fresnel lens or the glass in front, there's a micro switch to prevent you doing so. They're safe if correctly operated.

 

Redheads are 3200k, you need either a CTb or a dichroic filter for daylight.

[Vadim Joy]

But why then people don't just use tungsten lights with filters to get 5600K instead of heavy, radioactive hmi lights which require ballast to operate?

[Jeff Wolfram]

"why then people don't just use tungsten lights with filters to get 5600K...?"

 

those blue gels eat up a lot of light

[Stuart Brereton]

It would be a few cents. Really; the power consumption of such little wattage for a day is barely a blip on a power bill-- especially if you're @240v where the Amps are essentially halved-- though depends what your mains are in your country.

Just a note that electricity is sold in Kilowatt Hours, so the voltage makes no difference.

[JB Earl]

quartz lamps also produce UV radiation (not quite radioactive),

but not as much as (unshielded) HMI. If you shoot artwork you'll find out.

 

You can do a lot with 3 redheads and some scrims and diffusion. Keep some spare lamps around because they will pop. Keep a lower wattage lamp in case you want to use one direct with the others bounced or diffused

[Brian Drysdale]

But why then people don't just use tungsten lights with filters to get 5600K instead of heavy, radioactive hmi lights which require ballast to operate?

 

Because you need a much more powerful tungsten light for the same amount of 5600 light. Those large tungsten lights are just as large as the HMIs, which come in a range of sizes from 200w up to 18k, so they're not all big. If operated correctly there's no danger from HMIs,

 

Here's an old thread on the subject: http://www.cinematography.com/index.php?showtopic=7957

[Brian Drysdale]

A 2.5k HMI is roughly the equivalent of a 10k with CTB.

[Vadim Joy]

A 2.5k HMI is roughly the equivalent of a 10k with CTB.

Wow

[Vadim Joy]

Keep some spare lamps around because they will pop. Keep a lower wattage lamp in case you want to use one direct with the others bounced or diffused

Yeah I think this is a good idea. I will keep them 800w as they are but will buy few 250w just in case I need them.