Kenko 400mm f/8.0 Mirror Lens

The 400mm f/8.0 Mirror Lens from Kenko may sound like it is just another super telephoto lens, but unlike most others it is just over three inches long and weighs less than a pound. This makes it far more convenient to use in fast-paced scenes--such as birding, wildlife, or sports--because it does not require a cumbersome tripod to hold it up.