Slo-Foto.net have published an interesting comparison of six telezoom lenses; the Sigma 28-200mm, Sigma 70-200 F2.8 HSM EX, Canon 70-200 F4 L USM, Canon 70-200 F2.8 L USM, Canon 75-300 IS III and Olympus 50-200 ED.

“At this focal length (70mm) all models lack sharpness to a certain degree, which is quite understandable. Sigma’s model is a slight dissapointment, as at the biggest apetrure F2,8 it shows significantly less sharpness in comparison to competitors. This difference decreases with smaller apertures, and even reverses at the smallest one. All lenses gave best sharpness between F8 and F16. Especially Canon’s model with F2,8 gave good results over all the tested apertures.”

Website: Slo-Foto.net - Telezoom Lens Review