The Tokina 10-17mm f/3.5-4.5 AT-X 107 AF DX Fisheye Lens for Canon is a rectangular (non-circular) fisheye lens, providing a 180° diagonal field of view. The broad angle of view gives an inherent curved, fisheye effect and can be used to capture expansive spaces from a relative close range. This lens' front element features a WR (water repellant) coating for easier cleaning and less susceptibility to water spots and smudges. The rear optical group contains one super-low dispersion (SD) glass element in order to reduce chromatic aberrations and provide a cleaner appearing image. Note: This lens is compatible with APS-C-sized sensors only and will not provide a full, rectangular image when used in conjunction with a full-frame sensor.