Depending on your camera, you could use it (the camera) as a rough lux/ft. candle meter itself. A light value (LV) of about 20 equates to about 10k foot candles. With a little math you can obtain the light intensity.
Personally, I use a portable lux meter for recording light intensity. Its a great unit that can help determine relative lux/ft candle.
http://www.bghydro.com/BGH/itemdesc.asp?ic=HLLALMDHA
but then I wouldn't be able to buy a cool toy like a light meter.The meter you need costs more than a bulb....