Is the extra 100mm focal length compared with the 300mm f/4L IS worth getting this similarly priced lens? Not really—you’d do better getting a 1.4X tele-extender for the 300mm. Lacking IS, this one has outlived its usefulness.
Standout Spec: Light weight for a 400mm.
Sony 70-400mm f/4-5.6G SSM
Sigma 120–400mm f/4.5–5.6 APO DG OS HSM
Canon EF 400mm f/5.6L USM
Canon EF 100-400mm f/4.5-5.6L IS USM