Sigma 180mm f/2.8 APO EX DG OS HSM Macro Lens Review

Sigma 180mm f/2.8 APO EX DG OS HSM Performance

As far as sharpness is concerned, this lens really delivers. Sharpness is already excellent acros the frame at maximum aperture and reaches outstanding levels across the frame when stopped down to f/5.6.

Resolution at 180mm

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 D700 using Imatest.

Chromatic aberrations exceed 0.75 pixel widths towards the edges of the frame when stopped down beyond f/11. Although this level is still low, it may become visible in large prints or harsh crops from the edges of the frame that contain high contrast edges.

Chromatic aberration at 180mm

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 D700 using Imatest.

Falloff of illumination towards the corners of the frame is fairly typical for a telephoto lens with a maximum aperture of f/2.8. The corners are 1.8 stops darker than the centre of the image at maximum aperture and visually uniform illumination is achieved with the lens stopped down to f/5.6 or beyond.

Distortion is very well controlled, with Imatest only detecting 0.183% pincushion distortion. This low level of distortion should be virtually imperceptible.

No issues out of the ordinary were had regarding flare and loss of contrast when shooting into the light. A deep hood is supplied with the lens, along with an extender for times when the lens may be used on an APS-C format camera.

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