I've done a few beam shots. /ubbthreads/images/graemlins/smile.gif
Your settings depend on what you are trying to show. You might be showcasing the beam pattern of a light all by itself or you might be showing several lights together. You can highlight the following; corona; hotspot, beam tint, relative brightness, color rendering or beam shape.
With most cameras you will get a good shot of the hotspot and corona using the automatic settings.
I usually start with a moderately dark hallway. Depending on the light, I might be 3 feet from the wall or 12 feet. I use a tripod to hold the camera but you can balance it on a shelf or book or hand hold it.
You can emphasize the corona by setting the camera to extra light. You can zero in on the hot-spot by setting it to dark.
Virtually every digital camera has white balance controls to compensate for incandescent light vs florescent vs sunlight. It helps to place a white paper somewhere in your picture so the camera can figure out what light source to balance to.
To get the beam tint, it's sometimes necessary to fix your white balance at 'sunlight' or 'incan' and then take your picture against a white background.
If you are doing multiple lights, adjust the camera light/dark (f-stops to those familiar with the jargon) so that the brightest light is not washing out the others. If you want to make the weak lights look better, turn the brightness up so that the weak lights are OK but the brightest is washed out. /ubbthreads/images/graemlins/smile.gif
If you want to compare several lights at different times, learn to set the F-stop, shutter speed, ISO and white balance manually. This will allow you to take pictures that are consistant with the light being the only variable. This also works for comparing several lights pointing at the same target (such as a distant building).
Daniel