The Canon EF-S 18-135mm f/3.5-5.6 IS USM is the new kit lens for the EOS 80D camera. Is it just a throw-away lens that you should upgrade as soon as possible, or is it actually worth using? We’ve tested the EF-S 18-135mm f/3.5-5.6 IS STM on the EOS 80D to find out…