Hi i like to buy a canon 100-400mm L usm is lens, but the question is: If i like to buy hem second hand, where do i have to watch out for??? i mean its possible for me to buy a lens from 1 year old, but i have to know if its a good lens(inside) what is the best way to see if the lens is okay?????
i know the best way is to buy a new one but paying 1500 or 1000 is a big difference for me!