With new STM technology does Canon’s updated 18-135mm still deliver?By Paul Carroll - Monday January 14 2013 Lens Review
Refreshed to include Canon’s latest evolution in autofocus technology, the Stepper Motor, the Canon EF-S 18-135mm f3.5-f5.6 IS STM offers ultra quiet continuous autofocus during video capture. With its predecessor the Canon EF-S 18-135mm f3.5-f5.6 IS still available and for less money however, if you’re not interested in video capture, which version of this lens should you go for and how does this latest model compare to the competition? Our Canon EF-S 18-135mm f3.5-f5.6 IS STM review has the answers for you.
Launched in June 2012 the Canon EF-S 18-135mm f3.5-f5.6 IS STM is an updated version of Canon’s Super Zoom ‘kit’ lens originally announced in 2009 alongside the Canon EOS 7D DSLR. Designed for the Canon EF-S lens mount on Canon DSLRs using an APS-C sensor EF-S lenses aren’t compatible with Canon full-frame cameras like the EOS 1Dx. On APS-C cameras however taking account of the 1.6x Canon ‘crop factor’ the 18–135mm focal length offers an equivalent range of 29 – 216mm in 35mm terms, which makes it a versatile all-in-one lens for travel and general use photography.
Aimed at the enthusiast market the 18-135mm f/3.5 - f/5.6 IS STM features a variable maximum aperture, which lets less light through the aperture as the lens is zoomed in. This keeps the cost down but at the longest focal length of 135mm the f/5.6 aperture lets in 4-times less light than f/2.8 on a pro lens. The new lens does however feature Canon’s lens-based Image Stabilisation system, known as IS, which the manufacturer states offers 4-stops of anti-shake performance and to some degree this makes up for the variable maximum aperture.
The main development however is the inclusion of Canon’s latest evolution in autofocus technology, known as the Stepper Motor or STM Technology. Until now only available on the Canon EF 40mm f/2.8 STM lens, STM technology brings ultra quiet operation for continuous autofocus during video capture. With both lenses currently available however if you’re not interested in the Stepper Motor, which lens should you go for? We delve under the hood of the DxOMark Lens Metric Scores for the Canon EF-S 18-135mm f3.5-f5.6 IS STM to answer those questions for you.