Sigma 50-150mm f/2.8 EX DC APO OS HSM Lens Review

Sigma 50-150mm f/2.8 EX DC APO OS HSM Performance

At 50mm, sharpness is already outstanding in the centre of the frame at maximum aperture although towards the edges performance just exceeds good levels. Peak sharpness across the frame is achieved with the aperture stopped down to f/5.6 for this focal length. Here sharpness is excellent across the frame.

Similar performance is maintained at 100mm, with excellent sharpness in the centre although clarity falls just below good levels at maximum aperture. Stopping down to between f/5.6 and f/8 results in peak performance as sharpness is excellent across the frame.

Finally, at 150mm, there is a slight drop in performance in the centre of the frame at maximum aperture, with performance in the centre approaching excellent levels. Clarity towards the edges of the frame is improved over other focal lengths at maximum aperture, with performance approaching very good levels. Peak performance for this focal length is realised between f/5.6 and f/8, where sharpness improves to excellent levels across the frame.

MTF@50mm

MTF@100mm

MTF@150mm

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 Nikon D300 using Imatest.

Chromatic aberrations are reasonably controlled, just exceeding 0.75 pixel widths at 50mm and f/2.8, as well as f/22. This low level of CA should pose few issues, even in large prints, or harsh crops from the edges of the frame.

CA@50mm

CA@100mm

CA@150mm

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 Nikon D300 using Imatest.

Falloff of illumination towards the corners of the frame is fairly well controlled. At 50mm the corners are 1.08 stops darker than the image centre and at 150mm the corners are 1.39 stops darker than the centre. Visually uniform illumination isn't achieved until the lens is stopped down to f/5.6 or beyond throughout the zoom range.

Mild barrel distortion is present throughout the zoom range, with 1.31% barrelling being present at 50mm and 0.347% at 150mm. This low level of distortion should be difficult to spot, but if straight lines are paramount, then you'll be glad to hear that the distortion pattern is uniform across the frame at both ends of the zoom range, which should make applying corrections in image editing software pretty straightforward.

A deep petal-shaped hood is supplied as standard with the lens, which does a decent job of shading the lens from extraneous light that may cause unwanted flare and loss of contrast. During testing there were no issues with flare and contrast holds up reasonably well, even when shooting into the light.

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