Conclusion

Put simply, the Canon EF 400mm f4 DO IS II USM is an outstanding super telephoto lens. Its use of cutting edge optical technology provides superb image quality with minimal light fall-off, no noticeable distortion and very high corner to corner sharpness.

But where typical professional grade super tele lenses tend to be cumbersome and unwieldy, Canon’s innovative implementation of diffractive optics has kept the EF 400mm f4 DO IS II USM refreshingly compact and light. It’s small enough to fit comfortably inside a photo backpack, and when combined with the excellent Image Stabilization system, you can even use the lens hand held in favourable conditions.

Predictably, all this performance and quality is far from cheap, which sadly puts this lens out of reach to all but pros and enthusiasts with very deep pockets. Consequently if you need a 400mm reach and can live with a slightly narrower maximum aperture, it’s worth considering Canon’s excellent EF 100-400mm f/4.5-5.6L IS II USM, which can be had for roughly a quarter the price of the EF 400mm f4 DO IS II USM.

Ratings (out of 5)
Design	4.5
Features	5
Ease-of-use	4
Image quality	5
Value for money	4