Canon 200-400mm lens with extender

Canon has announced the development of a very special new zoomlens, the EF 200-400mm 1:4L IS USM Extender 1,4×. This 200-400mm telezoom has a built-in 1.4x extender (converter), which can be switched into place without having to take the lens from the camerabody. With the extender in place the lens becomes a 5.6/280-560mm. This is ideal for wildlife photographers and sport photographers, because it is much faster than having to attach a conventional extender and it lowers the risk of getting dust on the sensor. Perhaps a bit surprising is that Canon is using this unique new extender in a zoomlens. Extenders are mostly used with fixed focal length lenses, and Canon also introduced new versions of its 2.8/300mm, 2.8/400mm, 4.0/500mm and 4.0/600mm lenses. Built-in extenders in these lenses would no doubt also be very useful.