Canon has introduced the EF 200-400mm f/4L IS USM Extender 1.4x - a top-end telephoto zoom with a built-in switchable teleconverter, whose development was first announced back in February 2011. Simply flicking a lever at the rear of the barrel converts it to a 280-560mm f/5.6 lens. Designed for professional sports and wildlife photographers, it includes an array of top-end features such as Power Focus for movie shooting, and IS 'mode 3' that only applies stabilisation at the point of exposure, aiding panning. It also offers weathersealed construction, 4-stop image stabilisation, and a minimum focus distance of 2m. It will go on sale on 29th May, at an RRP of £11999.99 / €11800.