SIGMA 50mm f/1.4 Dg HSM a £600/$950

It’s something of an ‘Art’ class in portraiture

You certainly can’t accuse Sigma’s 50mm Art-line lens of being a lightweight contender. Despite having the same focal length and aperture rating as Canon’s 50mm f/1.4 lens, the Sigma is physically twice as long and nearly three times heavier. Indeed, it’s almost twice the weight of Canon’s 85mm f/1.8 lens, and can feel quite a handful on relatively compact bodies like the EOS 750D, for which it gives a portrait-friendly ‘effective’ focal length of 80mm.

The reason for the upsizing and weight gain is that the Sigma has a much more complex design compared with the Canon 50mm f/1.4. Whereas the Canon has seven optical glass elements, the Sigma has no fewer than 13. Its filter attachment thread is 77mm compared with the Canon’s 58mm, which gives an indication of how much larger its front element is. It also has a better-rounded aperture, based on nine diaphragm blades instead of eight.

Another Sigma upgrade is that it features a fast and whisper-quiet ring-type ultrasonic autofocus system, whereas the Canon 50mm f/1.4 only has a motor-driven ultrasonic arrangement. However, the Sigma is nearly twice the price of the Canon in the UK, and almost three times as expensive in the USA.

Performance

At its widest aperture, the Sigma has better centresharpness than any other lens in this test group, along with superb contrast. Cornersharpness is comparatively disappointing, although it picks up well if you close down the aperture by a stop or two. Colour fringing is also very well contained and distortion is practically nonexistent. All-round performance is exceptional.