Summary: Sigma's latest image-stabilized fast telezoom offers a fine option for budget-conscious buyers, with a unique combination of features for the price. It can't quite match its Canon and Nikon equivalents, but then again it's not as expensive either.
Pros: Very sharp across the frame when stopped down, Minimal color fringing/chromatic aberration of any description, Fast, silent, accurate autofocus with manual override, Very effective image stabilization, Decent build quality, Clever design tripod mount which is quick and easy to remove with the lens on the camera
Cons: Somewhat soft and low in contrast at F2.8 towards the edges, especially on full frame cameras, Can give somewhat harsh rendition of out-of-focus backgrounds at longer focus distances, No focus limiter switch, No weathersealing, Susceptible to flare with direct light sources in or close to the frame, Front-positioned zoom ring is inoperable when hood is reversed, Depth of field scale inaccurate at close focus distances
Excerpt: Sigma's 70-200mm f/2.8 EX DG MACRO HSM is solidly built and well designed, although the zoom ring could do with being about an inch further forward to make it truly comfortable to use. The overall size and weight of the lens mean that you need to use the tripod collar for optimum balance - rather than mount your camera onto your tripod with the lens making it front-heavy, though the collar can be removed if you prefer.
Summary: During testing this Sigma lens has proved itself quite capable of producing excellent results. For the most part, the sharpness in the centre is very good, or even excellent. Unfortunately its Achilles heel is the performance wide open at 70mm, where it is a bit lacklustre for a lens costing £1200.
Pros: Excellent centre sharpness at most focal lengths and apertures, Very low CA levels, Fast AF, Optical Stabiliser, Decent build quality
Cons: Lacklustre resolution performance at 70mm and f/2.8
Summary: The Sigma 70-200 mm OS 2.8 is a very good combination with the Sigma SD1 Merrill camera. In terms of resolution / sharpness, this lens to better advantage on a Sigma SD1 Merrill than with the Canon 60D or the Canon 5D MK2. The Sigma 70-200 mm 2.8 OS on a Sigma SD1 Merrill is an attractive lens, especially when you consider that the Sigma 70-200 mm 2.8 OS lot cheaper.
Pros: HoogHigh resolution in the center from f/2.8, with the exception of 200 mm, Fairly small difference between centrumscherepte and corner sharpness at most focal lengths, Beautiful woolly display onscherrpe parties, Very low distortion, Slight vignetting, Low chromatic aberration, relatively light in weight,, Very good price / quality ratio
Cons: Autofocus is not very fast, Sensitive to light, Not waterproof