Camera Lens for Shadow Puppet animation?

Bobby Thunder wrote:

I am just starting a project to make a short animated shadow puppet film and I'm trying to work out the best Lens type to use when down shooting with my Canon EOS 550 camera. I have a strong light source below the table and three glass shelves with the lower two for tracing paper backgrounds and the highest one for black silhouette puppets. I want to be able to have sharp focus on the black silhouettes and to play with the focus on the background layers. I have been advised that an older glass lens is the way to go but I'm not sure which focal length is the right one. Currently thinking perhaps a 28mm canon lens but any advice would be hugely appreciated!

I'd go with a cheap "fast 50" -- something like an old M42 SMC Takumar 50mm f/1.4 or 55mm f/1.8.

Manual focus allows you better control over focus -- and a good old lens like the above will stay at the distance it is focused on for multiple shots. The 50mm preference is simply because that roughly where the fastest lenses are cheapest, and you want fast to be able to get shallow depth of field. Simply adjust the height of your rig for 50mm to get the right crop of the scene; if 50mm makes that too large a distance, a shorter focal length will work, but they'll give les control over depth of field (even at the same f/1.4 aperture, not to mention 28mm f/1.4 lenses are expensive and very rare). The old Takumars also deal pretty well with strong backlighting, which not all fast lenses do.