Conclusion

The Canon EF 50mm f/1.8 STM is an appealingly simple, compact and capable lens that's equally at home on an APS-C or full-frame DSLR camera. It's also very cheap, making it a worthy addition to any EOS user's camera bag.

Despite its very affordable price, the Canon EF 50mm f/1.8 STM build quality is reassuringly good, thanks largely to the new metal mount. It's a great match for either a full-frame Canon DSLR like the 5Ds that we tested it with or an APS-C body, where the focal length changes to a more portrait-friendly 80mm.

Auto-focusing is perhaps this lens' Achilles heel. It's quiet but not especially quick, especially in Live View mode. For video shooters, though, the STM motor is appealingly smooth and quiet. The ability to manually override the AF system via the focus ring if required is a nice touch, and we didn't really notice or mind that the focusing ring is electronically-driven.

Image quality is generally good. Chromatic aberrations are well controlled, geometric distortion is impressively low, and the Super Spectra coatings successfully prevent contrast loss attributable to flare. The only real optical issues are some obvious corner shading at the maximum aperture on a full-frame body, and a lack of critical edge sharpness between f/2.8-f4 and f/16-f/22. Still, not bad going for a £125/$125 lens!

In summary we can heartily recommend the Canon EF 50mm f/1.8 STM as a lightweight, very compact standard prime lens for all Canon DSLR owners, at a price that certainly won't break the bank.

Ratings (out of 5)
Design	4.5
Features	4
Ease-of-use	4.5
Image quality	4
Value for money	5