My friend Scott recently sent me a Twitter message asking where to get a chromakey background and how big it should be. I hope I was helpful, suggesting a few different places I have bought such things. Honestly, just between us, I am a big fan of eBay for this sort of thing. Yeah, I love B&H and Adorama, but the real bargains for things like this, which do not need warranties, is eBay.
The other part is a little more complicated. This goes for any kind of background, not just for chromakey. When I set up a shot, I typically start assembling the equipment with the background. It’s just going to sit there, as the least dynamic piece of the shoot. See the picture below:

The subject goes in front of the background, then the camera and the lights are off to the sides (not pictured in drawing). You want to have about four to five feet between the subject and the background. This will eliminate shadows from your lights. Then your camera has to be some distance back, depending on the type of lens you use and how tightly you crop the image.
Based on all this, you may need a larger background from time to time. For most shots you want a perfect isosceles triangle between the camera and background. Those angles shouldn’t change a bit. All you might change is the distance between the camera and subject.
Here is an easy way to see how large a background you will need for your shoot. Set up your camera where you think it should go and have a friend put markers at the edge of what you can see. Or do it yourself, for crying out loud! Measure between the two points and you have the width of your background.
If your area marked is too wide, move the camera closer or else change to a lens with a more narrow angle. You can also improvise a bit by simply cropping in Photoshop when you are done with the shoot.
On a related note, keep an eye out for an upcoming post on what different types of lenses can do to your picture. We will look at wide angle, normal and telephoto lenses and discuss how they make the photo look different.
Technorati Tags: background, chromakey, shadows, isosceles triangle


