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Sigma 17-50mm F2.8 EX DC OS HSM Lens Review (for Nikon)

Sigma 17-50mm F2.8 EX DC OS HSM lens  


 

March 2012
(tested with Nikon D7000)

The Sigma 17-50mm F2.8 EX DC OS HSM lens was announced in February 2010 and released in July that year. The lens is available in Nikon, Canon, Sony, Pentax, and Sigma mounts. In December 2011 Sigma announced non stabilized versions (non OS) for Sony and Pentax since most of their cameras have built in stabilization. This is a DC lens, which means it's designed specifically for DSLRs with APS-C sensors (DX, etc). On Nikon's DX (cropped) sensor the effective zoom range is 25.5-75mm, making it a standard mid range zoom lens. It's an EX lens which means it has superior build and optical quality. It has a built in Hyper-Sonic Motor (HSM), so it will autofocus with all Nikon Digital cameras, including the lower end consumer models, such as the D3100 and D5100. The lens also features Sigma's FLD glass elements. Sigma claims it has equal performance to fluorite glass in correcting all types of aberrations. (For all of Sigma's letter designations see here).

The lens is made mostly of plastic but it's built fairly solid. My copy doesn't rattle or wiggle. The exterior and interior barrels are made of plastic. The zoom and focus rings are rubber coated. The lens mount is metal. There are two switches on the lens, an auto focus/manual focus switch, and an OS on/off switch. There's also a zoom lock tab which can only be used at 17mm. I usually don't lock the lens. I haven't experienced any zoom creep so far, but it's good to know the lock is there just in case. The zoom is on the stiff side but turns smoothly. The focus ring is a little looser than I like and has a very limited range. I also wish the focus ring was a little wider. Overall though I had no problems manual focusing the lens. Also, the focus ring does rotate when focusing so you'll need to be mindful of where you place your fingers. There is no manual focus override as with some of the Nikon lenses. You must engage the AF/MF switch to manual focus. Being an HSM lens focusing is fast an accurate, but the lens did hunt a bit under very low light conditions. The filter threads don't rotate so using filters is no problem. The OS (Optical Stabilization), works very well. Sigma claims a gain up to 4 stops.

Sharpness in the center of the lens is excellent throughout the zoom range wide open and gets better stopped down to f/4. It remains excellent until f/8 when diffraction starts to decrease the sharpness level. Wide open the borders are good, with the corners being on the soft side. Stopped down to f/4 and both borders and corners are very good. This pattern is consistent throughout the zoom range until f/8 where again, diffraction starts to occur. I found the sweet spot for the lower end of the zoom range is f/4, with f/5.6 showing the best overall sharpness for the mid and long end of the zoom.

Barrel distortion is a bit on the high side at 17mm with some pincushion distortion at 50mm. Mid range the distortion is relatively flat. Overall the distortion should be easily correctable. Vignetting is most noticable at 17mm wide open. Stopped down to f/4 and it's all but eliminated. Chromatic aberration is well controlled and not a problem. Flare also is not a problem. The bokeh the lens produces is good wide open at 50mm. As expected the wider end of the zoom range produced less pleasing bokeh.

After reading and hearing many great things about the Sigma 17-50mm f/2.8 OS I decided to give it a try (as an added incentive at the time I purchased it there was a $75 instant rebate). Optically the lens performed very well. The weak point was the soft corners at f/2.8. To me that's not a big deal. Corners and borders usually matter most for landscape photos which are usually shot using smaller apertures. I compared it with my current mid range zoom lens, the Sigma 17-70mm F2.8-4 DC Macro OS HSM. Although the 17-70mm is a fine lens I chose to replace it with the 17-50mm. The 17-50mm is sharper and seems to have more contrast. The images it produces just look better. Also, the constant f/2.8 aperture can come in handy at times. By giving up the 17-70mm lens I'm losing 20mm on the long end of the zoom. Honestly, I do prefer the longer reach, but thanks to the 16MP sensor of my Nikon D7000 I have plenty of room to crop if need be. I'm also giving up the close-up feature of the 17-70mm. Again, I can crop the image to make the subject "larger", or I can attach a Nikon 5T or 6T closeup lens to the 17-50mm. I often carry one or both in my bag.

The Sigma 17-50mm F2.8 EX DC OS HSM lens is what's mounted on my camera most of the time now. It serves as a nice all purpose walk around lens. It's wide enough for most situations and long enough for everyday photography. The constant f/2.8 aperture allows for good subject isolation, making it a decent portrait lens (although I still prefer to use a prime lens such as the Nikon AF-S 85mm f/1.8G). If you're still using a kit lens and looking for something a little sharper and faster (larger aperture), the Sigma 17-50mm OS would be a fine choice. You can help support this site by buying the Sigma 17-50mm F2.8 EX DC OS HSM lens from this Amazon link or the B&H Photo link below.

 



Specifications:

Focal length 17-50mm
Maximum aperture f/2.8
Minimum aperture f/22
Lens Construction 17 elements in 13 groups
Angle of view 72.4o - 27.9o
Closest focusing distance 28cm (11 in)
Maximum reproduction ratio 1:5
Number of diaphragm blades 7
Auto focus type HSM (Hyper-Sonic Motor)
Filter diameter 77 mm
Macro No
Dimensions 83.5 mm (3.3 in) x 91.8 mm (3.6 in)(Diameter x Length)
Weight 565g (19.9 oz)



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