In low light D50's focus light will only work 5 or 6 times, after that I must wait about 20 seconds before it will work again, is this normal?

Thank's Andy.

Interesting. That's not something I've ever heard of, but I'm not a regular Nikon user. Maybe the camera has to build up a charge for the focus assist like it would for a flash. Is it a red light or a white light?

I called Nikon. They said the AF bulb has a thermal protector that shuts off the bulb off when it gets to hot after repeated use.