Maybe money can buy you happiness after all.
I'm very impressed with Canon's hulking but versatile supertelephoto, the EF 200-400mm f/4L IS USM Extender 1.4x. If what makes you happy is sharp-focus shots of skittish wildlife, racing motorcycles, and air show jets, this lens delivers.
But its price tag -- $11,800 -- means only professionals and the best-funded hobbyists will get the chance to buy that happiness.
The lens' tremendously useful trick is a built-in 1.4x telephoto extender that, with the flip of a lever, changes it from a 200-400mm f4 lens into a 280-560mm f5.6 lens. That single trick means that this lens costs nearly twice what Nikon charges for its 200-400mm f4 competitor.
The price isn't too far out of line with other very high-end telephotos -- $11,000 for Canon's EF 400mm f/2.8L IS II USM, for example, or $10,400 for its EF 500mm f/4L IS II USM Lens. However, the sad reality is a lot of Canon customers were hoping for something priced more like Nikon's $6,500 AF-S Nikkor 200-400mm f/4G ED VR II or that offered better performance than Canon's EF 100-400mm f/4.5-5.6L IS USM design, with its elderly first-generation image stabilization and middling sharpness. It's hard not to bridle after seeing how Canon raised the price of its 24-70mm f2.8 lenses from about $1,300 to $2,100 moving from its first-generation to second-generation design.
Price aside, the lens is super.
In my testing on a Canon EOS 5D Mark III, I found the lens sharp either with or without the 1.4x extender engaged. There's no need to stop down, either; the maximum aperture of f4 at 200-400mm or f5.6 at 280-560mm performs admirably. Its autofocus operation is snappy, its magnesium-alloy build is rugged, the image stabilization is effective, and its 2-meter close-focus distance is good for nearby subjects like hummingbirds at a feeder. Distortion was minimal, and bokeh was creamy. My only complaint about the optics was significant vignetting when shooting wide open.
Using the built-in 1.4x extender quickly becomes routine. At the, I'd have the lens all the way out at 560mm for a small stunt plane's acrobatics, then flip the lever and take the zoom to 200mm for a hulking Airbus A380 taxiing nearby. Walking in the Bois de Boulogne forest, I'd quickly shift from 560mm for small birds to 300mm or 400mm for comparatively fearless mallards. It takes almost no time to learn how to move your hand from the shutter release button to the 1.4x lever to change the range. There's a lock to keep it at one setting or the other, but I never had any trouble with the mechanism.
The built-in extender is useful enough that I could imagine it cropping up elsewhere in Canon's lens line. It adds a lot of complexity to the design -- the lens goes from 25 lens elements at 200-400mm to 33 lens elements when the 1.4x extender is engaged. But Canon tuned the 1.4x extender's optics for this particular lens to keep image quality higher than with external extenders, and I could see a pro photographer enjoying the ability to change a 300mm f2.8 to a 420mm f4 even at the cost of one stop of exposure. The only real awkwardness I had with the extender was remembering to open up the aperture to f4 from f5.6 when disengaging the extender.
At 8.3 pounds (3.6kg), the lens is heavy. If you don't have a monopod or tripod (or mammoth shoulder muscles), you'll quickly tire of holding it up. And it's bulky, 14.4 inches (36.6cm) long without its lens hood. The size and weight are par for the course for supertelephoto lenses, but that doesn't make it any easier to track fast-moving subjects like pirouetting helicopters and skittish birds.
Fortunately, the image stabilization helps a lot. For stationary subjects, I was able to shoot at 560mm at 1/40 sec. with blur-free results about half the time, even without leaning against walls, cars, or trees for stability. When the while I had the lens for testing, I shot handheld with my own 1.4x extender attached for a 784mm f8 configuration with consistently good results at 1/250 sec.