The Canon EF 100-400mm f/4.5-5.6L IS is an earlier iteration of the improved Canon EF 100-400mm f/4.5-5.6L IS II. It features the same focal range, aperture range, and angle of view as the newer model (and is even a bit shorter and lighter than the newer model) but it sports an older image stabilization system with a now-antiquated (but still often loved) push/pull design. The push/pull design offers an intuitive approach to zooming, which some photographers find to be quicker than standard internal zooming. The zoom barrel also has a zoom position index printed on it so that you can quickly zoom to a particular focal length. Both lenses feature a dedicated tension ring for customized zoom torque. The Canon EF 100-400mm f/4.5-5.6L IS can be paired with both full frame sensor cameras, such as the Canon 5D Mark III, and with crop frame sensor cameras, such as the Canon 7D Mark II. The focal length equivalent on crop frame sensors is 160-640mm. Please see our notes on compatibility with the 2X and 1.4X Canon extenders. This lens also offers dual-mode image stabilization, suitable for panning. Autofocus is fast and silent, image quality is consistent from 5.9’ to infinity, and the color rendition is accurate. This is a great option for telephoto shooters who need a good amount of range in a relatively smaller package or for those who enjoy the push/pull design of this lens.