The Canon EOS Rebel T4i's
body is very similar to the T3i's; the biggest difference is on the inside, with the new hybrid sensor. The sensor has the usual set of nine phase-detection autofocus sensors in the center, but adds a larger set of contrast-detection AF sensors around them for use with the new STM lenses, like the 18-135mm f3.5-5.6 shown here. The lenses include a stepper motor for silent AF operation during movie shooting. Support for contrast AF allows them to perform continuous AF during movie capture as well.