Canon Super Telephoto Lenses

All telephoto lenses with fixed focal lengths, called "prime" telephoto lenses, are divided into three categories by Canon: Telephoto lenses, standard and medium telephoto lenses and finally super telephoto lenses. Telephoto lenses have to do with magnification, in other words, making an object appear closer to you as it really is as seen with the naked eye. The lens that approximates the vision with the naked eye is 50mm, which is why this is the focal length of all standard lenses.

The factor of magnification achieved by all telephoto lenses can be expressed by dividing the focal length of a telephoto lens by 50mm, so a 400mm telephoto lens has a magnification power of 8x – the object appears 8x closer as it really is as seen with the naked eye. "Super telephoto lenses" are what the name indicates: super ones, with vocal lengths in excess of 400mm. These include lenses like the EF 400mm f/2.8L IS USM, EF 600mm f/4L IS USM and EF 800mm f/5.6L IS USM.