After a long wait, Sigma’s new flagship telephoto zoom in its Sport series lens has arrived. Michael Topham had the honour of giving it a workout
Sigma 70-200mm f/2.8 DG OS HSM Sport review: Image Quality
To get a good impression of how the lens performs optically, it was used over several weeks with multiple Canon full-frame DSLRs, including the Canon EOS 5DS R, Canon EOS 5D Mark III and Canon EOS R. I should also add that the lens can be used on crop-sensor (APS-C/DX) cameras and is equivalent to a 105-300mm telephoto zoom on cameras that feature a 1.5x crop factor and 112-320mm on APS-C cameras that employ a 1.6x crop factor.
Inspecting my real world images on the computer confirmed what I was seeing on the back of the camera. It’s a lens that produces impressively sharp and attractive results. One of its key strengths is the way it controls chromatic aberrations. Colour fringing is so well handled along high-contrast edges and at the corners of the frame you won’t find yourself rushing to use the defringe sliders or remove chromatic aberration during raw processing.
The fairly fast fall-off in focus when shooting at the lens’s maximum aperture at its maximum focal length also requires you to be watchful of your focus point positioning. Get it right and you’ll be rewarded with a wonderful depth to images that really makes your subject pop and stand out from their surroundings.
Studying our Image Engineering results tell us the lens resolves its sharpest results at the widest end of its focal range. Stopping the lens down to f/4 and f/5.6 sees the centre sharpness improve at all focal lengths. Edge sharpness never matches the same level of sharpness that’s resolved in the centre, and the dotted lines on our MTF graph reveals that corner sharpness, like centre sharpness, is better at the wider end of the zoom range than it is at full telephoto. You’ll also begin to notice the impact of diffraction softening overall sharpness when the lens is used at f/16 or f/22.
Vignetting is obvious when the lens is used at its maximum aperture. It’s more gradual at 200mm than it is at 70mm and users will find that this corner shading can be alleviated fairly quickly by closing the aperture by a couple of stops. The lens displays mild barrel distortion at the wide end, which turns to pincushion distortion at telephoto lengths, however this isn’t a major concern and will be an easy enough one-click fix when a lens profile is available in Lightroom and Adobe Camera Raw.