The Canon EF-S 18–135mm lens is a standard to short telephoto telezoom for Canon digital single-lens reflex cameras with an EF-S lens mount.
The original version of the lens, the f/3.5–5.6 IS, was introduced in 2009 with a suggested retail price of US$499.99.
A new version of the lens, the f/3.5–5.6 IS STM, was announced on 8 June 2012, alongside the EOS 650D/Rebel T4i/Kiss X6i.
The "STM" stands for "Stepping Motor", a new autofocus technology claimed by Canon "to smoothly and silently focus" and "achieve continuous AF while recording video" when used with the 650D (and presumably future Canon bodies).
The latest addition of the 18–135 series is the EF-S f/3.5-5.6 IS USM, announced on 17 February 2016.