I typically so mine on fine. The finer its set at, the shorter the video and the more memory it'll take up. At the smallest setting, you might get 60 minutes on a 1 gig card.

As for lighting, if you have it set on the video setting, press the function button, "AWB" is the first setting you can change and it will allow you to pick the type of lighting you'll be in. Does that help?