Canon EF 50mm F1.4 USM review

The Canon EF 50mm F1.4 USM may be based upon a 37-year old optical design, but its performance in our studio tests clearly shows that it's not giving up yet. Sure the hairs are beginning to grey a little, and Sigma's new young pretender can outmuscle it comprehensively at wider apertures, but this lens really shows its quality once the aperture is closed down a couple of stops. Naturally it reserves its very best results for its native 35mm full frame format (indeed our tests on the 1Ds Mark III suggest it has plenty in reserve for future increases in sensor megapixels), however it is also perfectly capable of fine imagery on the more resolution-demanding APS-C sensor. Essentially it delivers much what we expect from a prime, i.e. a significantly better optical performance than all but the most exensive zooms, in a small, light and relatively inexpensive package. And let's not forget the advantage offered by its fast and quiet autofocus.

So what's not to like? Obviously the biggest problem is a lack of sharpness at those wider apertures; F1.4 is distinctly soft and 'dreamy', especially on APS-C, and whilst central sharpness increases rapidly on stopping down, the corners do lag behind by a couple of stops. (Of course it's important to bear in mind that depth of field at these apertures is so shallow that corner softness is rarely a real problem; unless you're in the habit of placing your main subject towards the corner of the frame, the chances are that these regions will be well out of focus anyway.) The lens is somewhat susceptible to flare with strong light sources in or near the frame, and some users may find the vignetting at wide apertures on full frame problematic, especially if they have been brought up on relatively unaffected APS-C cameras; then again others may appreciate the framing effect it can bring to a shot. Barrel distortion on full frame is also sufficiently strong that it could occasionally be annoying in real-world shooting, although to be fair, RAW shooters can correct it in the lens aberration correction module of Canon's free Digital Photo Pro RAW processing software when required. Finally, build quality still leaves a little to be desired, and it would be nice to have 'real' ring-type USM for silent AF. These are all areas where the Sigma 50mm F1.4 EX DG HSM trumps the Canon, so if you're planning on buying a 50mm to use predominantly at the widest apertures, it's likely the better bet.

Of course the other big question is whether the 50mm F1.4 USM is worth the extra money over its little brother, the EF 50mm F1.8 mkII. We'll be testing this lens fully in due course, but it's giving nothing away to say the F1.4 has superior build quality, and a much better AF system; these in themselves could be sufficient reason to buy the faster lens, especially for users planning on putting it to frequent use.

So ultimately this is a lens which has its own distinct strengths; it's ideal for users looking to buy a relatively small, lightweight prime, in order to gain image quality simply unavailable on a zoom for the same price. It's an excellent companion to full-frame DSLRs, especially the EOS 5D (and indeed demonstrates that full-frame cameras don't necessarily demand prohibitively expensive lenses); it also doubles pretty well as a portrait lens on APS-C cameras. Overall, it's a strong performer, and (perhaps most importantly) optically far superior to any inexpensive kit zoom lens.

Andy Westlake

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