Canon 800mm f/5.6L IS

Canon’s newest, longest telephoto lens. It’s lighter than the Canon 600 f4 IS by a pound although a bit longer. Early reports indicate that it’s every bit as sharp as the other Canon supertelephoto lenses, and the IS provides a full 4 stops of image stabilization (which can be important in a lens this long, even when mounted on a tripod).

It is fully compatible with the 1.4X teleconverter, although it will only autofocus on 1D series cameras with an extender mounted. Autofocus is not guaranteed, even on 1D bodies with the 2X teleconverter, although some report that center point autofocus may work, at least in bright light.

Roger’s take: Now that I’ve taken this out a couple of times, I’ll answer the question everyone asks “Why the more expensive 800 f5.6 instead of a 600 f4 IS with a 1.4X converter”

1) Its a bit lighter and the IS is clearly better (4 stops) than the 600 (2 stops) which means in a pinch I can handhold it for a shot or two, more if I can brace myself on a fencepost, etc.
2) The 800 f5.6 IS is sharper than the 600f4 with 1.4X.
3) The IS system does a better job of controlling mirror slap, allowing shots at 1/5 – 1/20th second (on a steady mount of course) that get blurry with the 600.
4) 1600 mm with a 2X, although you have to manually focus.

Now that I’ve shot with the 800, I like it. I definitely prefer it over a 600 with teleconverter if I know I need the focal length. The 800 f5.6 is also the photography equivalent of a D cup: Not a necessity, but wherever you go with it, you’ll make lots of new friends.