Sigma Contemporary 20-200mm 3.5-6.3 DG

When it comes to purchasing a "super zoom lens", you should manage your expectations. Such lenses are never going to be as good as shorter zoom lenses or even primes - obviously. This also applies to the Sigma 20-200mm f/3.5-6.3 DG Contemporary. Having said this, it's not terrible either. Sigma has spent decades improving the designs over and over again. For the best results, you should still stop down to at least f/8 where the overall quality is actually quite decent. If possible avoid the maximum aperture at the very wide and very long end of the zoom range if corner quality means something to you. Autocorrection is also needed to tame the high vignetting and high CAs at 20mm and 200mm. The native image distortions are actually lower than you might expect but even so autocorrection should be used to mask the increasing corner softness. The build quality is pretty good which is something we got used to with modern Sigma lenses. The plastic quality is fine and there's only a hint of wobbling of the inner lens tube despite the long extension when zooming out towards 200mm. Some degree of weather sealing is also reassuring. The AF is perfectly fine. Some may miss a dedicated optical image stabilizer but the camera's IBIS is mostly "good enough". So what does this mean regarding the battle between the Sigma 20-200mm f/3.5-6.3 and the Tamron 25-200mm f/2.8-5.6 then? We'd say it's mostly a tie in the overlapping range as well as build quality. The Tamron offers a bit of extra speed whereas the Sigma has the 20mm setting on its side so this comes down to personal preferences. Both are best used on lower-megapixel cameras where the compromises in sharpness are less obvious.

Highly recommended – Crisp results and a versatile, extended range from ultra wide 20mm to telephoto 200mm.