What kind of lense would I need to put in front of a video projector to shrink the image?

I wish to be able to use my video projector to project onto an A4 sized screen. Is there some kind of lense which I can put in the beam to focus it back down to a small size rather than the huge image I currently get?

Ideally the projector needs to be as close to the A4 screen as possible.

The best one is going to be convex on one side, and flat on the side towards the projector. You aren't going to need any kind of dramatic curvature either. I'd go with something extremely mild, then work from there.

If you haven't heard of Edmund Scientific, they are an excellent place to get lenses, and you can find about any size or curvature or type of lens that you can imagine.
They have a good website too.

http://scientificsonline.com/Default.asp?bhcd2=1184819637

follow the link for optics.

Good luck
Kevin

I got my lenses backwards in my head the first time.

http://www.glenbrook.k12.il.us/gbssci/phys/CLass/refrn/u14l5b.html

check that out for some basic optics. it straightened me out !