The original 2009 version was highly regarded generally, but it was not without some shortcomings. With a score of DxOMark 16 for the older, larger lens compared with a score of 18 for the 2012 version the difference is close and so the new model is considered to be only a minor update. There are however some slight improvements, which is good news given the reduction in size, weight and price.
Scoring 6P-Mpix the resolution sharpness figures show a slight increase, meaning it’s slightly sharper where it needed to be. That’s to say, mainly in the 135mm to 250mm range, where longer focal lengths tend to fall off in definition. Reducing the size usually results in some penalties with regard to distortion and vignetting. Fortunately, the transmission rating remains the same and the only downside is a slight increase in lens shading (vignetting) at the maximum aperture. We would like to have seen a decrease in pincushion distortion but maybe we’ll see that next time around. As for sharpness-depriving chromatic aberration there’s actually a slight improvement, proving it was the right choice to replace the SLD glass in the rear groups with a double sided aspheric.
When tested on the Canon EOS 7D (and other EOS models using the same size sensor) we can see how the lens performance favors the smaller chip. As a result the pincushion distortion is very slightly less as is the unsightly chromatic aberration. However, in fact, the lens is the same optically. Our only real gripe is the same regardless of mount and that’s the distracting pincushion distortion is higher than we would expect.
When comparing the new Sigma with the best performing that we’ve tested, the Nikon AF-S DX NIKKOR 18-300mm f/3.5-5.6G ED VR, we can see that even a lens from such a highly regarded optical firm is not without some issues.
The sharpness is quite good at 6P-MPix, vignetting is low and distortion, while high, is lower than the Sigma, and it’s 1/3rd of stop faster. But we can see it is somewhat troubled by high chromatic aberration, despite the inclusion of ED glass. Even without looking too hard the unsightly fringes are noticeable in the corners of the frame and are even worse at 50mm and 105mm settings. As for sharpness, prime lenses are likely to be much more capable of providing good results with today’s (and tomorrow’s) demanding sensors. The Sigma 105mm F2.8 EX DG Macro Nikon for instance can easily achieve a 50-percent improvement in resolving power with a score of 9 P-Mpix on the Nikon D7000. However, at around $1,000, the 2012 Nikkor lens is a pricey option.
See to our own review: AF-S DX Nikkor 18-300mm f/3.5-5.6G ED VR Review.
With a street price of around $650, compact dimensions and a bit of extra reach Tamron 18-270mm F/3.5-6.3 Di II VC PZD Nikon is the ‘affordable’ choice but with that comes a number of concessions. First, although the lens has good contrast and sharpness centrally from the maximum aperture onwards the resolutionsharpness is definitely on the low-side (even most bundled kit lenses achieve a score of around 6P-MPix) and it’s not particularly well-corrected for chromatic aberration (at 18mm and over the 135-to-270mm range, with it being noticeable across 2/3 of the field from 200mm-to-270mm). What’s more, at around $700 it’s an attractive price for a ‘marque’ lens
Canon users also have an excellent lens to choose from. While it’s a few years old now (announced in 2008, introduced early 2009) the Canon EF-S 18-200mm f/3.5-5.6 IS is a decent performer, as you might expect. With a 200mm maximum, this lens doesn’t have quite the same range of focal lengths but it has a four-stop image stabilizer unit and features Canon’s swift AF, focusing to just 0.45m. Two UD glass elements and multiple aspheric surfaces keep chromatic aberrations to tolerable levels, only being noticeable over the 50-to 200mm range. Moreover, sharpness is very close to the newer Sigma at 5P-MPix albeit with somewhat soft outer zones, however the lens exhibits a little more vignetting (at -1.6EV at 18mm f/3.5) and, of course, it has the usual barrel to strong pincushion distortion signature.