Sigma 24-35mm f/2 DG HSM | A Review – Image quality
An inspection of real-world images taken at 24mm with the aperture set to f/2 reveals excellent sharpness in the centre. The edges of images at these settings are perceptibly softer than the centre, but things quickly sharpen up as soon as you approach f/2.8 and push towards f/4. The sweet spot of centre and edge sharpness at 24mm is found at f/8. Our lab results confirmed our real-world findings that there’s the faintest drop in sharpness in the centre at 30mm, however the edge sharpness remains impressive at this focal length when it’s opened to f/2. Pushing the zoom to 35mm sees the centre sharpness rival that recorded at 24mm beyond f/4, with optimum sharpness once again being found in the region of f/8.
The corner shading is clear to see in this image which was captured at the lens’s maximum aperture (f/2)
Vignetting is most obvious at 24mm. There is a gradual improvement as the aperture is closed from f/2 to f/4, with virtually all traces of corner shading disappearing by the time you reach f/5.6. It’s a similar story at 35mm, though the fall-off of illumination at f/2 isn’t quite as dark as it is at 24mm. Some red and green chromatic aberrations were noted at the edge of some shots, but it’s by no means severe and should be a relatively easy fix by applying the relevant lens profile in Camera Raw and Lightroom when it becomes available. Our distortion chart also flagged up evidence of some barrel distortion towards the corners at 24mm and some pincushion distortion at 35mm.
An image taken with the aperture set to f/2, clearly illustrating the shallow depth of field
To answer my earlier question of how it compares to the Sigma’s 24mm f/1.4 DG HSM | A and 35mm f/1.4 DG HSM | A: the 24-35mm f/2 DG HSM | A resolves impressive sharpness, but a side-by-side comparison of our Applied Imaging charts revealed a slightly superior sharpness from both primes in the centre with less obvious distortion at the corners. As for corner shading, this lens displays more vignetting when it’s used wide open than when both primes are set to the same aperture setting of f/2.
