Recommended lens for photographing infants/newborns?

What lens would you recommend for shooting infants? Currently, I have the Nikon D3000, but will be upgrading to the D3100. I was looking at the Nikon 50mm 1.8D, however I noticed that it doesn't auto focus with a lot of cameras. Would it be compatible with the d3100?

Also, I need a Nikon lens, or one compatible with Nikon cameras.

The only 50mm lens that will autofocus with the D3000 or D3100 is the AFS Nikkor 50mm f/1.4G: http://www.bhphotovideo.com/..._1_4G.html

The older 50mm f/1.8D doesn't autofocus, but will work perfectly fine otherwise if you don't mind manual focus.

Instead of wasting money upgrading your camera body (the d3000 is not that old), I would spend the extra money on a couple of good lenses (or a good external flash if you don't have one already).

The 50mm sounds good, but something a little wider (like a 35mm lens) helps with moving infants. Yeah you should probably get a lens that has autofocus if that is important to you (I personally hate autofocus, so I rarely use it - but it is nice to have the option if I ever need it, such as shooting with one hand).

newborns don't move much, so you won't' need autofocus for them. Infants move more, but you can get away with manual focus (that's how I usually take pictures of people, including infants).