These are lenses that attach to Canon DSLRs. Lenses are broken down into different groups based on the needs. Lenses are rated for "full frame" cameras. If your camera is a crop-sensor camera then know that the focal length will be cropped or "zoomed in". Prime lenses offer a single focal length are are a great budget friendly option if you want to create a certain look to your footage with a typical wider aperture and better low-light performance. Zoom lenses give you a range of focal length that would allow you to "zoom in" or "zoom out" to your subject. A typical lens for filming hunts is an 18-135mm.