If you're looking for something a little more than just a standard zoom, Sigma offers a few lenses with macro capabilities built in...
If you’re looking for something a little more than just a standard zoom, Sigma offers a few lenses with macro capabilities built in. This lens offers 1:3 macro magnification as well as standard zoom shooting, equating to 27-75mm in 35mm terms. The design is claimed to increase peripheral brightness, while the inclusion of Special Low Dispersion, Extraordinary Low Dispersion and aspheric elements correct distortion and chromatic aberrations. Sigma is a member of the Four Thirds groups, so the lens is available for Olympus and Panasonic cameras, as well as those from Nikon, Canon, Sony, Sigma and Pentax.
The velvety, slightly rubberised coating on the plastic barrel is tactile and attractive, while the grooved rubber zoom and focus rings are comfortable. The focus ring only turns when the camera is in manual focus mode; attempting to operate it in AF meets resistance, and forcing it will break the gears. The zoom ring is dampened and smooth, and the secondary inner barrel extends as the zoom is moved to the tele end. Unlike some other Sigma lenses, this model lacks the Hyper Sonic Motor (HSM), which makes this optic’s AF slightly noisier and slower than the Nikon, Olympus or Canon lenses in this category.
The Sigma impresses with its high central resolution, but at wide apertures that resolution falls off towards the corners. However, it maintains an excellent average resolution, particularly at 18mm. The optic’s best performance, or sweet spot is at f/8 at 18mm, and f/11 at 50mm. The 50mm end is excellent with very little fringing, in most cases below a 1 pixel rise, though this does increase slightly to around 1.5 pixels at 18mm, showing the difficulty of wideangle lens manufacture. In this case, though, fringing is barely evident in most pictorial scenes.
If you’re looking for something completely different, Sigma provides a very viable option. For less than the price of the camera brands lenses, the 18-50mm features macro capability, making it unique in this round-up. Not only that, but the fast aperture and excellent performance make it good value for money.