more to add on, for a ultra-wide lens, i feel that the user need to possess some knowledge in order to yield proper result.
as the UWA lens exaggerates the depth of the photo, improper placement of human subjects within the frame MAY result in in-proportional size of body parts. not forgetting that the slight tilting of the lens will skew the perspective of the photo as well.
You haven't spend much time reading the basics of Canon equipment... The lens has an EF mount, the camera can take EF lenses as well as EF-S lenses. Have a look in your manual and the Canon website, specifications for lenses.