This is a popular lens for photographing wildlife and birds. The images are wonderfully sharp from edge to edge. We did some comparison testing between several lenses at 400mm, including the Canon 100-400mm EF f/4.5-5.6L IS II, a Canon 70-200mm f/2.8L IS II with a the Canon 2x III extender, and the Canon 300mm f/4 IS with a Canon 1.4x III extender. The 400mm f/5.6 produced the sharpest image across the entire image. All of these lenses were very sharp in the center of the image, but the others softened a little bit in the corners. Note that good technique was required to produce the optimum images. We used a tripod, very fast shutter speeds, small apertures, and released the shutter with the self timer.
This lens works well with extenders so you can turn it into a 560mm or an 800mm lens, but you will lose the auto-focus and the effective aperture will be quite small. Our conclusion is that this is a good choice when you need superior sharpness and a longer reach but canít be tied down with a larger, heavier lens. It is relatively light at 2.8 lb and is a very well built L series lens.
Accessories supplied with lens:
- Front lens cap
- Rear lens cap
- Tripod mount ring
- Soft padded case