This extreme 650-1300mm f/8-16 Manual Focus Lens from Bower is an economical way to achieve some ultra-telephoto photography, all the way up to 1300mm. This is a T-mount lens, which means that aperture is not communicated to or controlled by the camera body, and in this particular configuration is delivered with a T-mount for Canon EOS cameras. Use this lens only in aperture-priority autoexposure mode or in fully manual exposure mode.
It will work on both "full frame" as well as the smaller-format APS-C (15 x 22mm) cameras, but has only one effective aperture at any focal length, which varies from f/8.0 at 650mm to f/16.0 at 1300mm. That's not much of a hinderance, however, as you'd likely use this lens at its relatively small maximum aperture in any case.
This lens requires bright light and a high ISO setting on the camera to get a fast shutter speed, and needs a sturdy tripod or monopod, but can deliver very sharp results if used properly.