About a month ago Canon announced the EF 200-400mm f/4L IS USM Extender 1.4x - the world's first SLR lens with a built-in teleconverter. With the simple flick of a switch on the top of its barrel, the lens can be turned into a 280-560mm f/5.6 optic. This is a deceptively simple trick, but one that seems to have caused Canon plenty of headaches, as the lens had an unusually long gestation period: it took more than two years from its initial 'development announcement' in 2011 to the lens's general release. During that time, we're told, it was put through its paces at last summer's biggest sporting events, and many aspects of the design refined and improved.

The 200-400mm is, frankly, a monster: it's over 36cm / 14" long and weighs 3.6 kg / 7.9 lb. It uses no fewer than 33 elements arranged in 24 groups, including Fluorite and Ultra-Low Dispersion glass. It has everything you'd expect of a professional sports optic - a weathersealed magnesium alloy barrel, ultrasonic focus motor, and image stabilisation that promises four stops benefit. The latter means that despite its bulk, it can plausibly be shot hand-held, at least for short periods of time.

It's pretty obvious that this isn't a lens for the mass market - it's a specialised sports and wildlife optic, and at a cool £11999.99 / €11800, more likely to be bought by agencies than individual photographers. In fact we'd not normally cover a product this stratospherically-positioned, but it's the first of its kind, which rather piqued our interest, and Canon was kind enough to let us try one out for an hour or two. Read on to find out more.

Headline features

  • 200-400mm focal length range, F4 constant maximum aperture
  • Built-in extender converts lens to 280-560mm f/5.6 at the flick of a switch
  • Optical IS - four stops claimed benefit, three modes
  • Ultrasonic motor for focusing, including power focus for movie shooting

Zoom range

The examples below give some idea of the lens's zoom range, shot from the same position on the EOS-1D X at 200mm, 400mm, and 560mm (i.e. with 1.4x extender engaged):

200mm 400mm 560mm

Canon EF 200-400mm f/4L IS USM Extender 1.4x specifications

Recommended retail price  • UK: £11999.99
 • EU: €11800
 Maximum format size  35mm full frame
 Focal length  • 200-400mm
 • 280-560mm with extender engaged
 35mm equivalent focal length (APS-C)  • 320-640mm
 • 450-900mm with extender engaged
 Diagonal angle of view  • 12.3° - 6.2°
 • 8.8° - 4.4° with extender engaged
 Maximum aperture  • F4
 • F5.6 with extender engaged
 Minimum aperture  • F32
 • F45 with extender engaged
 Lens Construction  • 25 elements in 20 groups
 • 33 elements in 24 groups with extender engaged
 • Fluorite and Ultra-Low Dispersion glass elements
 Number of diaphragm blades  9
 Minimum focus  2.0m / 6.6ft
 Maximum magnification  • 0.15x
 • 0.21x with extender engaged
 AF motor type  • Ring-type Ultrasonic motor
 • Full time manual focus
 Focus method  Internal
 Zoom method  Internal
 Image stabilization  • Yes
 • 4 stops
 • 3 modes
 Filter thread  • 52mm
 • Drop-in filters
 Supplied accessories*  • E-145C front cap
 • Rear cap
 • ET-120 (WII) hood
 Weight  3620g (7.9 lb)
 Dimensions  128mm diameter x 366mm length
 (5.0 x 14.3 in)
 Lens Mount  Canon EF

* Supplied accessories may differ in each country or area