Using a 500 Watt Halogen Light and Flash

[Benji]

A fellow Camelian sent the following to me in a PM. "I have a question about your setup for the headshots. You set all of your lights and your camera to match, then you crank up a 500w light to close down her iris. I get the purpose of shutting down the iris, but doesn't that 500w light throw off your previous settings?"

Answer. The 500 watt light won't affect the exposure unless you use a shutter speed that is balanced to the shooting aperture. My shooting aperture is usually f/8.0 so by setting the meter to the ambient setting and placing the aperture at f/8.0 the correct shutter speed is 1.3 seconds. Since I use a shutter speed of 125th of a second in my camera room the 500 watt light simply cannot show up. Just like turning your headlights on at noon. They don't help illuminate the road in front of you because the main light source overpowers them. My estimation is that my combined flash units are 64 times more powerful than the 500 watt light. (Seven stops.)

Benji

[Austen]

Hi Benji,

So, if I understand you correctly, when you shoot in your camera room it's actually quite light ?

For a home living-room shooter, would it be a good idea then to dim the room lights, and then set the exposure, and then turn the room lights back on ?

I've been getting very wide iris's, as I have the room reasonably dim, but I will try this next time !!

Thanks for another great tip,


Austen.

[Benji]

Austen,

I use flash units that have rather dim modeling lights which usually will not close the iris down in my subjects. So after I have flash units set up and I have checked the lighting pattern on the subject's face I switch the 500 watt light on, or sometimes the overhead and fill light modeling lights on. For checking the lighting pattern with flash your camera room should be as dark as an old time photographer's darkroom.

Benji

[Austen]

I bow to the Master !!!

I was having a good play with my camera (and 180 WS flash) as I had other issues (white balance)....

I had my camera at around 1/200, 100, 5f...Or thereabouts, and recalled this post.

The pictures were coming out pretty well exposed, plus or minus an f-stop, so I covered my IR transmitter so there would be no flash, and the exposure was pure black, working as I was with basically a bit of window light from the loft window and the modelling light.

I then turned all the room lights on, and with my hand again over the IR transmitter took a couple more photographs....Of pure black, as Benji said the room lights weren't effecting the exposure at all !!!!

Another lesson learnt, Thanks heaps Benji !!!

Austen.