From The Digital Picture
Bryan has completed his full review of the Canon EF 200-400 f/4L IS 1.4x (we're still working on ours). As expected, the review is a glowing one as this lens performs unbelievably well for a zoom.
“If the f/4 max aperture is not an issue for you, the Canon EF 200-400mm f/4 L IS USM Ext 1.4x Lens, by virtue of its focal length range, can replace several other lenses in your kit. It will deliver stunning image quality and should stand up to professional use. I'm still integrating this lens into my kit, but … I have been using it for almost everything I shoot since it arrived. I expected awesomeness and the 200-400 L delivered it.”
Canon EF 200-400 f/4L IS 1.4x $11,799 USD