Shown in these images is the cast of "Altar Boys", a really fun musical comedy. But I'm presenting them here in rough form to show how I light white background images.
Yep. That's me up on that bench pointing a Nikon D700 with an old 24-85mm zoom lens at the actors. That's my ancient Gitzo carbon fiber tripod and you can see why I love it. Even without the center column extended it reaches up seven feet tall. I like shooting down. It's a fun angle. The shorts and sandals are mandatory summer wear here in Austin.
The front light is very simple. It's a huge 84 inch Lastolight umbrella with its own, built in white diffusion panel. It's beautifully soft. Even when used twelve to fifteen feet from the subject. Why the heck would I use it so far away? Well, if you remember the inverse square law, the further away the light source the less fall off there is from side to side in the image. And you can see how evenly the actors are lit. The only other frontal modifier is a silver 48 inch reflector panel to the opposite side.
The nuts and bolts of getting a good, white background are simple: You want very even lighting across the entire background. That's why I'm using four umbrellas. You want to make sure the light from the umbrellas doesn't spill forward and strike the subjects directly. That's why we carefully focus the light sources into black backed umbrellas. Finally, you want to forget all the nitwits who say you don't need a meter if you have a digital camera and you want to pull out your incident light meter and make sure that the white background (according to your incident light meter) is one third to one half of one stop brighter than the light on your subject. Anything brighter and you risk the light bouncing off the background, wrapping around the edges of the subjects and degrading the whole image. Once your histogram hits 255 how do you measure 1/3rd of a stop more? You can do it easily and quickly with an incident light meter!
A more in depth explanation of this set up is in my book: Minimalist Lighting: Professional Techniques for Studio Photography, from Amherst Media.
If you want to dive into how I shoot portraits we're doing a day long workshop in Austin, Texas on February 13th. Hit this for the sign up page.....