Sigma 17-70 mm f/2.8-4.0 DC Macro OS HSM
- decent quality of build,
- sensational image quality in the frame centre in the 17-28 mm focal lengths range,
- very good image quality in the frame centre at longer focal lengths,
- useful image quality at the frame edge,
- efficient image stabilization,
- chromatic aberration well corrected in the middle of the range and at longer focal lengths,
- low astigmatism,
- quite well corrected coma,
- correct work against bright light,
- relatively silent and efficient autofocus.
- combination of maximum relative aperture and maximum focal length is not very useful,
- visible vignetting in the whole focal lengths range.
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The mere comparison between pros and cons, especially for such a price point, allows us to state that the lens can defend itself without any problems and is indeed a very interesting option for everybody who thinks about changing his/her cheap kit lens for something better.
We can try to find out what is the Sigma’s position individually in every system especially that this lens is offered with all mounts cooperating with an APS-C/DX sensor.
In the case of Canon the Sigma will have to compete with the EF-S 17–85 mm IS USM and the EF-S 15–85 mm IS USM models. The first device is currently cheaper than the Sigma but its performance and fastness are definitely worse. It won’t be a serious threat even though its focal lengths range is a bit wider. The focal lengths range and very good optics are the strong points of the new EF-S 15-85 mm for a change. From this aspect it is certainly better than the Sigma. The Sigma features significantly better light and lower price, though. It seems that both instruments will find a lot of enthusiasts.
The Nikkor has as many as three lenses with similar parameters on offer, namely the 18–70 mm, the 18–105 mm VR and the 16–85 mm VR. The first of them is a bit cheaper than the Sigma but here its advantage ends – its range and fastness are worse and it lacks the image stabilization system. The second model, optically very well-made, features image stabilization and a wider focal range. Its price/quality ratio is good too but its build quality is inferior and it is slower than the Sigma. The most serious rival can be the Nikkor 16-85 mm VR. It is optically good (although not better than the Sigma), costs currently more or less the same, it is solidly build and features the image stabilization. Nikkor’s wider focal range can oppose the fastness of Sigma. Once again it seems that both devices will find more or less equal number of fans.
The Sigma might have most problems when it comes to Sony reflex cameras. Its image stabilization is not as important in the case of a stabilized sensor as it is on a Canon or Nikon body. Additionally it must compete with two 16-80 mm and 16-105 mm models, both very good optically and mechanically. They are not as fast as the Sigma but their focal lengths ranges are significantly more interesting.
When it comes to Pentax the situation once again becomes curious. Pentax offers its own 17-70 mm model but with f/4.0 aperture so slower than the Sigma and, overall, it isn’t better optically being more expensive at the same time. The sensor stabilization is not as important an argument as in the case of Sony because the OS stabilization in the Sigma lens is even by 2 EV more efficient than that of the Pentax’s sensor and you don’t have to wait for the unfortunate “hand” in the viewfinder. The image is stabilized right after putting your finger on the shutter and initial pressing.
To sum up the Sigma 17-70 mm OS HSM seems to be a very good solution for every amateur photographer who owns an APS-C/DX class sensor reflex camera. It’s true that in every system the lens must face a serious competition but such a situation is very good. For us, the customers, it is even perfect.