DxOMark has recently tested the Sigma 120-300mmm DG OS HSM - a unique extended-range image-stabilised fast telephoto zoom -  and as part of our ongoing collaboration we've added the lens test data to our lens widget. We've also added a range of Nikon telephoto lenses including the AF-S Nikkor 200-400mm f/4G ED VR, which can be compared with each other and their Canon counterparts. See below for more analysis. 

Also this week, DxOMark has published its sensor review for the Olympus OM-D E-M1 (we've also recently published our own in-depth review). It's also reviewed the Canon Powershot G16. Click here for a round-up of DxOMark's recent reviews, including the Sigma 120-300mm F2.8 DG OS HSM and Olympus OM-D E-M1.

Sigma 120-300mm F2.8 DG OS HSM lens test data

Click on any of the images or links below to open our interactive lens widget, and explore the data further

We have test data for both Canon and Nikon mount versions of the 120-300mm, on both full frame and APS-C/DX format cameras. The sharpness data is different between the two brands, but we put this down to copy variation between the two lenses used - the Canon-mount sample looks sharper at F2.8, but the difference evens-out quickly on stopping down (there's a small difference in measured MTF50 at F4, but we doubt it would be visible in images compared side-by-side). This is visible when looking at APS-C results, but on full frame it's evened out by the higher resolution of the Nikon test body (36MP D800 vs the 22MP EOS 5D Mark III). 

The 120-300mm performs exceptionally well on full frame. Central sharpness is very impressive at all focal lengths, and while the edges and corners don't quite hit the same heights, they're very good indeed. The very sharpest results, as expected, are obtained around F5.6-F8. Some measure of how well the lens performs can be seen by the fact that it measures up to benchmark fast zooms such as the Canon EF 70-200mm f/2.8L IS II USM and the AF-S Nikkor 70-200mm f/2.8G ED VR II. It can't quite match the very best fast primes like the Canon EF 300mm f/2.8L IS II USM or Nikon AF-S Nikkor 300mm f/2.8G ED VR II for peripheral sharpness, but it's really not far off (especially when stopped down a little), and is significantly less expensive.

Lenses aren't purely about sharpness of course, but the Sigma does extremely well in all respects. Chromatic aberration is visible at 120mm, but diminishes to nothing at 300mm. Vignetting is nothing to worry about, at a maximum of 1.4 stops wide open at 300mm. Distortion is well controlled too: it's essentially perfectly-corrected at 120mm, but there's a little pincushion distortion at 300mm

Switch to APS-C/DX format and the story is broadly similar. As mentioned above, the Canon-mount sample tested is sharper than the Nikon one at F2.8, but it's debatable whether this would matter in real-world images.  The nearest thing to a flaw is lateral chromatic aberration at 120mm, but this is easily removed in post-processing if necessary. As usual both distortion and vignetting are distinctly lower on the smaller format.

Overall, then, the Sigma 120-300mm F2.8 DG OS HSM is an optically-excellent lens that performs extremely well in these tests. There's nothing else quite like it on the market - it gives longer range than conventional 70-200mm F2.8 telezooms, and offers a particularly interesting value proposition compared to the camera manufacturer's 300mm F2.8 primes (it's less expensive, but very close in optical quality). It's also compatible with Sigma's USB Dock (click here for our review), which allows detailed AF micro-adjust and tuning of the lenses autofocus and image stabilisation systems.  

Nikon AF-S Nikkor 200-400m f/4G ED VR II lens test data

The Nikon 200-400mm f/4G isn't an especially new lens (t was announced in May 2010), but we thought it would be interesting to compare it to Canon's EF 200-400mm f/4L IS USM Extender 1.4x - the world's first photographic lens with a built-in switchable teleconverter - which we quickly reviewed earlier this year.  

The Nikon 200-400mm f/4 performs exceptionally well - as you'd probably hope from a $5000 lens. Like its even-more-expensive Canon counterpart, it's difficult to see what more you might ask from a lens - it's impressively sharp at all settings while keeping chromatic aberration, distortion and vignetting well under control. It's not as blisteringly sharp as the fast telephotos that coincide with its range -  the AF-S Nikkor 200mm f/2G ED VR IIAF-S Nikkor 300mm f/2.8G ED VR II, or AF-S Nikkor 400mm f/2.8G ED VR II, but you'd probably have to look very close indeed to see any difference in your images.

Full test data in our lens widget

Click the links below to see test data for a range of Nikon telephoto lenses on full frame and APS-C. There's not a lot to say about the primes, beyond the fact that they're all exceptional performers in ever respect. 

Full test results on DxOMark (and other recent reviews)

Our lens test data is produced in collaboration with DxOMark. Click the links below to read DxOMark's own review of the Sigma 120-300mm F2.8 DG OS HSM, or see other recent reviews on the DxOMark website.