see also:

• Canon EF lenses

• world's first SLR lens with a built-in teleconverter but at $11,800 and $5000 more expensive than the Nikon 200-400mm f/4, you would really need to have a lot of use for it
• introduced in 2011

• 200-400mm f/4 switchable to 280-560mm f/5.6
• 25 elements in 20 groups and with extender engaged, 33 elements in 24 groups; incl. flourite and 4xUD
• optical image stabiliser “4EV” with 3 modes
• USM AF
• power AF mode for video
• 9 blades
• close focus 2m giving 0.15x (0.21x with TC engaged) magnification
• 52mm rear drop in filters
• tripod collar
• focus limiter 2-6m; 6m-infinity; full range
• focus preset
• AF stop buttons
• 128x366mm long
• 3.62kg
• weathersealed
• $US11,800?

• dpreview.com
• http://photo.net/reviews/canon-200-400/
• http://petapixel.com/2013/06/03/review-canon-200-400mm-f4l-is-1-4x-stretches-focal-length-and-wallets/
• http://www.kenrockwell.com/canon/lenses/200-400mm-f4-is.htm
• http://www.grantatkinson.com/blog/canon-ef-200-400-f4-l-is-usm-extender-1-4x-field-review
• DxO Mark