Compatibility is an area where Nikon’s lens design strategy starts to break down. For whatever reason, Nikon decided to incorporate varying levels and degrees of technology into sets of lenses, resulting in a fairly confusing matrix of feature compatibility among lenses - not only the autofocus features, depending on the internal motors, but also metering and matrixing. Here’s the cheat sheet - but the quick version is “AF-S or AF-I: All functions supported.”
• Type G or D AF NIKKOR without built-in autofocus motor: All functions except autofocus supported. IX NIKKOR lenses not supported.
• Other AF NIKKOR: All functions supported except autofocus and 3D color matrix metering II. Lenses for F3 AF not supported.
• Type D PC NIKKOR: All functions supported except autofocus and some shooting modes.
• AI-P NIKKOR: All functions supported except autofocus and 3D color matrix metering II.
• Non-CPU: Autofocus not supported. Can be used in mode M, but exposure meter does not function. Electronic rangefinder can be used if lens has a maximum aperture of f/5.6 or faster.
Canon, for their part, simply says: “The EOS Rebel T1i is compatible with all Canon lenses in the EF and EF-S lineup.” That’s “over 60 lenses,” by their count. The Nikon count on current AF-S lenses is around 30. Canon is the clear winner with its expansive lens compatibility.