I am an extremely satisfied user of Canon 400 mm F 5.6 EFL lens. I have used this lens with variopus Canon bodies like Canon EOS 1RS, EOS 1N, EOS 3, EOS 1DS mark II, EOS 5D. I have had wonderful experience with all these bodies with excellent sharpness in the center of the frame.

Outstanding sharpness; well controlled flare characteristics; very little lateral colour; Minimal drop in sharpness with the 1.4 X EF teleconverter

lack of USM; I guess that is about it

This is more lens you get for your money. Sharp wide open and hand holdable. If for birding (BIF), this lens can not be beat except for those by $$$$$.

Durable; Fast / accurate auto-focus; Hand Holdable; Lightweight; Nice Bokeh; Rugged; Sharp wide open; Strong Construction; You will not miss IS

NONE

Wow was I surprised on my first shoot with this lens. I had a Great Blue Heron fly directly at me and not having my tripod on though that the pictures would turn out shaky but the were crisp and clear. A very nice lens and focus is very quick and without any hesitation.

I was looking at purchasing the Canon 100-400mm zoom then convinced myself I would be mainly using it at the 400mm end so why waste money when you can buy the Canon 400mm f5.6L for half the price Received my lens just over a week ago and have not used it much beyond the wildlife in my garden.

For the price it is top amongst its rivals.

Excellent image quality

Would be even better with Image Stabalization

Getting the Canon 400 5.6L raised the quality expectation I had of camera lenses, immediately getting rid of the three I already had which now didn't seem up to the job. The choice was between this and the Canon 100-400mm and don't regret buying this as I've only once found I would have liked to...

VERY sharp; light; fast focus; use with converter; lightweight; quality build

None

Excellent lens! Outstanding pictures! Great wildlife and landscape lens! Very satisfied! Canon L lenses are always top of the line! Recommend highly!

I bought this lens from amazon to use with my 30D primarily for wildlife,bird protography. I was absolutely impressed how sharp the pictures came out from this combo of my 30D + 400 f/5.6 lens. I went to the SF zoo one day, took pictures of the birds that were on display from about 12-15 feet.

ultra sharp autofocus; very light; hand holdable; in-built retractable hood; L series; tack sharp images; fine glass; comes with tripod mount,sexy white color

f/5.6 is a bit small for low light; autofocus hunts in low light; not a 500mm lens :

"Primary use: Birding and wildlife Camera body: Canon 7D Pros: Great clarity of glass, relatively light (for a 400mm), sharp wide open at f/5.6, built in hood is so convenient (don't overlook this advantage), quality build, and price.

Lens focuses very fast and accurate, great for birds in flight and other wildlife, light enough to carry all day and use hand held. However this lens is slow so it needs a lot of light. Wish canon would make the same lens with IS at a price mortals can afford.

extremely fast focus and light weight

needs lots of light to perform well