cathay is selling this lens at $1550. AF is very noisy, quite fast but not as fast as the sigma HSM. the sigma is much faster. as for optical quality, this lens is very sharp and contrasty from 100 to 200mm, even wide open. However, at the long end, u need to stop down at least 1 stop to obtain very sharp pictures. wide open at long end is not so bad if u r not very critical.
cathay is selling this lens at $1550. AF is very noisy, quite fast but not as fast as the sigma HSM. the sigma is much faster. as for optical quality, this lens is very sharp and contrasty from 100 to 200mm, even wide open. However, at the long end, u need to stop down at least 1 stop to obtain very sharp pictures. wide open at long end is not so bad if u r not very critical.