Tried to search for this, got too many hits, so if there's a thread already, point me. If I underexpose to shoot day for night, am I going to end up with a bunch of noise? Is there some technique for doing this in video or is there a filter that makes it possible? Thanks.

There may be much better ways, but this is what we have done successfully.

First we used a light yellow poster board to white balance the camera. This should give you an overall blue cast, which looks like bright moonlight.
You should experiment with different shades of color, if possible.

Then, using a good video monitor, or your color viewfinder, record the scene. Adjust your camera settings (mainly aperature) to get the look that you desire. Just be sure that you get the level of detail that you want.

Of course, you can adjust your video in post.

I recommend that you experiment to achieve the best results.

I do assume that there are better techniques, this is just what worked well for our project.

Hi Dave,
You're right; the search parameters seem to have broadened quite a bit! Here's a thread where Rob Lohman did the searching for us way back when:
http://www.dvinfo.net/conf/showthread.php?t=42234&highlight=%22shoot+day+night%22

Have a good time with it. It's actually kind of fun (whatever you do, remember to keep the skyline out of the shot!).

thanks folks, appreciate it.

You know, I recently learned that the opening sequence of Jaws was filmed day for night. This is an interesting concept!