Canon EF 50mm f/1.8 STM - Review / Test Report
Lens Reviews - Canon EOS (Full Format)

May 2015 by Klaus Schroiff


Honestly I can't remember how many 50mm lenses I reviewed during the last few years but there were many. Seems as if all the manufacturers are or have been in an update frenzy. All of then ? Well, Canon has been a little late in this game. This was especially true for the Canon EF 50mm f/1.8 II which was released back in 1990 ... 25 years ago! Think of that. :-) It almost feels as if they didn't really want to update it but were forced to do so by Yongnuo, a chinese manufacturer who just started shipping clones of the EF 50mm f/1.8 II (and the old EF 35mm f/2). So finally there's a new version ... sort of - the Canon EF 50mm f/1.8 STM. It isn't really a major update - at least optically. The new lens received a better lens coating and a marginally improved design here.

However, Canon has substantially redesigned the lens body. Unlike its predecessor, it has a metal mount and a decent, rubberized focus ring. The lens barrel is made of plastic with a nice matte finish. Th EF 50mm f/1.8 STM continues to use a linear focus extension system so the inner lens tube extends towards shorter focus distances. A barrel-shaped lens hood remains available as an option only.

The lens uses an STM (stepping motor) for auto-focusing. The STM has been optimized to deliver "smooth servo AF for movies and a speedy AF for stills". That's the theory according to Canon at least. Honestly the AF feels as fast as on to the EF 50mm f/1.8 II - at best. However, it is certainly more quiet although not as silent as Canon's USM AF. Anyway, it's certainly not bad in any case. Typical for all STM-driven lenses, manual focusing works "by-wire" thus you trigger the AF motor by turning the focus ring. This works nicely.

Optical construction6 elements in 5 groups
Number of aperture blades7 (circular)
min. focus distance0.35m (max. magnification ratio 1:4.7)
Filter size49mm (non-rotating)
Hoodbarrel-shaped, bayonet mount, optional
Other features-