Sigma 30mm f/1.4 DC HSM A Lens Review

Sigma 30mm f/1.4 DC HSM A Performance

At maximum aperture, sharpness in the centre of the frame is already very good. Clarity towards the edges of the frame is fair at maximum aperture, but this improves as the lens is stopped down. By f/4 clarity towards the edges of the frame reaches good levels, and very good levels of sharpness are realised towards the edges with the lens stopped down to f/8. Sharpness in the centre of the frame is very high throughout the aperture range, exceeding excellent levels when stopped down to f/2.8 or beyond.

Resolution at 30mm

How to read our charts The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Canon EOS 600D using Imatest.

Chromatic aberrations are reasonably well controlled, exceeding three quarters of a pixel-width towards the edges of the frame at maximum aperture, although this level decreases as the lens is stopped down.

Chromatic aberration at 30mm

How to read our charts Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software. Apochromatic lenses have special lens elements aspheric, extra-low dispersion etc. to minimize the problem, hence they usually cost more. For this review, the lens was tested on a Canon EOS 600D using Imatest.

Falloff of illumination towards the corners of the frame isn't as severe as you may expect from a lens with a fast f/1.4 maximum aperture. At f/1.4 the corners are only 1.03 stops darker than the image centre and illumination is visually uniform with the lens stopped down to f/4 or beyond.

Only a very slight amount of barrel distortion is present in images taken with this lens. Imatest detected 0.467% barrel distortion, which will be barely noticeable, even if straight lines run parallel to the edges of the frame.

A deep circular hood is supplied with this lens, which does an excellent job of shielding the lens from extraneous light that may cause loss of contrast or flare. Even when shooting into the light, contrast remains high.

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