Canon EF Lens Specifications & Accessories Table (.pdf)

The EOS 400D has a Canon EF-S Lens Mount.

http://en.wikipedia.org/wiki/Canon_EF-S_lens_mount

Whilst researching this aspect of the camera I found a Canon produced table of all the Canon lenses and accessories compatible with the EF/EF-S lens mount.

Note: All EF lenses fit onto a EF-S mount  but EF-S lenses do not fit on EF mounts.

http://www.usa.canon.com/app/pdf/lens/EFLensChart.pdf