Nature and wildlife photographer Joshua Holko a has spent some time with this long awaited Canon EF 200-400 f/4L IS 1.4x lens. Below is his hands on video review on this lens. According to him its image quality is equal or close to Canon’s excellent EF 300mm f/2.8L IS II.

Canon EF 200-400 f/4L IS 1.4x lens

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