The Canon EF 800mm f/5.6 L IS Usm is a super telephoto lens in production since 2008. It is a standard lens suitable both for FF format cameras and APSC. It is equipped with automatic focus via ultrasound AF engine that perfectly performs its task; There is image stabilization, also very efficient. It has a very reduced recovery angle of only 3.1 degrees and the minimum fire distance is 6 meters, high but it is to be considered that this kind of lenses must be used by long distances. The images are very clear and with colors faithful to reality, no defects of chromatic aberrations or distortion of any kind are detected. The weight is four and a half kilos and the measures are quite large but this does not affect much on the practicality or convenience of use, obviously such a lens is not suitable for freehand photos, it would be very tiring to use without a support like tripod or single -sided. The Canon EF 800mm f/5.6 L IS Usm is a lens suitable for photographers looking for great quality and strong reliability. The cost is very high and could be a deterrent for the purchase but the quality of the images is able to fully repay the investment. Perfect for naturalistic photos with moving subjects.