Canon 400mm f/4L DO IS

Super telephoto lens with diffraction optics that reduces its size and weight considerably compared to other lenses of this reach and aperture. Its the same size as, but a little lighter than, the 300mm f/2.8 IS. The size and Image Stabilization system allow it to be effectively handheld (at least for a while). This superbly sharp lens remains quite sharp with a 1.4x teleconverter, resulting in a nice 560mm f/5.6 lens.

Roger’s take: We dropped this lens for a while because we weren’t seeing much demand, but I’m glad its back— I used it all the time when we had one. Those who shoot RAW and do a little postprocessing (I’m one) are very happy with this lens. Those who shoot JPEG and want to print straight out of the camera are less so. The images are sometimes of lower contrast than the other top telephoto lenses. Its easy to boost contrast in a RAW image, but not so easy with a JPEG.

The bottom line: this is 400mm that can be handheld and give extremely good pictures. Its actually easier to handhold than the 300 f/2.8. It does well with a 1.4x teleconverter, giving you a 560mm f/5.6 Image Stabilized lens, and that’s a pretty big deal.