Ultra-wide Lenses Group Test (Part 2) – Sigma 8-16mm f/4.5-5.6 DC HSM, Sigma 10mm f/2.8 EX DC HSM

How wide?

Most of the lenses in this test group are ‘rectilinear’. That means that straight lines of objects in a scene remain straight in the resulting image, at least as far as possible. You’re still likely to see some bowing from barrel distortion, especially at the shortest end of the zoom range. And exaggerated perspective effects can also make straight lines appear to curve. These distortions are massively more pronounced on fisheye, or ‘curvilinear’ lenses, like the Sigma 10mm prime lens and Tokina 10-17mm fisheye zoom.

Even though the two fisheye lenses in the group have a minimum or fixed focal length of 10mm, similar to many of the rectilinear lenses on test, they have a much larger angle of view, at 180 degrees on the diagonal. There are actually two different types of fisheye: circular and diagonal. A circular fisheye lens produces a circular image at the central region of the image sensor. Both fisheye lenses on test are of the diagonal fisheye type, which cover the whole frame,  so you get a regular-sized, rectangular image.

A photo shot with ‘rectilinear’ lens

How we tested…

All the lenses in the group were tested on APS-C camera bodies, but we also used the full-frame Canon EF 17-40mm lens on a 5D Mark II. We were keen to include this lens, despite it not giving a wide angle of view on APS-C cameras, as it’s especially good value for a Canon L-series (Luxury) lens and therefore a tempting proposition if you have a full-frame body or are thinking of trading up. All lenses were checked for handling, autofocus speed and accuracy, and all aspects of image quality throughout their aperture ranges and zoom ranges (where applicable).

Sigma 8-16mm f/4.5-5.6 DC HSM

Rewriting the rule book on rectilinear ultra-wide lenses for APS-C cameras, the Sigma 8-16mm reigns supreme when it comes to sheer angle of view. At its shortest 8mm focal length this is 114 degrees compared with the 107 degrees of the Canon EF-S 10-22mm lens. But with the extra comes compromise.

Sigma 8-16mm f/4.5-5.6 DC HSM

The lens cap is a two-stage affair, combining a regular clip-on cap with a sleeve which also has to be removed. You can actually leave the sleeve on when shooting at the 16mm end of the zoom range, which also enables the fitting of 72mm screw-in filters or a square filter adaptor. However, at shorter settings, the sleeve causes extreme vignetting; essentially, you can’t use popular filters like ND grads at anything other than the longest setting.

Sharpness proved respectable rather than spectacular but remains good throughout the whole zoom range, even when shooting with the largest available apertures. Distortion and colour fringing are fairly well contained, and vignetting is only noticeable when shooting at 8mm with the largest aperture of f/4.5. Overall, it’s a good choice if you want to maximise your viewing angle at the expense of using filters.


·         Price: $339 at Amazon

·         For: Unbeatably wide angle of view for a non-fisheye lens

·         Against: Filters can only be used at the 16mm end of the zoom range

Sigma 10mm f/2.8 EX DC HSM

Quite chunky for a fisheye prime lens, the Sigma 10mm delivers a full rectangular image, rather than a small circular picture. It’s designed exclusively for APS-C cameras so, like all but the Canon EF 17-40mm lens in this group, it’s incompatible with full-frame bodies. Sigma states a full 180-degree diagonal field of view but, on Canon APS-C cameras which have a 1.6x crop factor rather than the more common 1.5x as other D-SLRs, it’s closer to 170 degrees. This still puts it a long way ahead of rectilinear lenses of the same focal length, squeezing much more into the frame.

Sigma 10mm f/2.8 EX DC HSM

As with any fisheye lens, the trade-off of a larger angle of view is that barrel distortion is very extreme; it’s this that gives fisheye images their distinctive look. In practice, the lens works well for giving a really funky effect in architectural photography, while shooting interiors is aided by the fast f/2.8 maximum aperture. This makes sharp handheld shots a real possibility, especially as the depth of field is considerable even at this large aperture.

Image quality proved sharp right into the corners and colour fringing was well controlled, while vignetting was only slightly noticeable at the maximum f/2.8 aperture.


·         Price: $649 at Amazon

·         For: Fast maximum aperture of f/2.8; good optical and build qualities

·         Against: Fisheye effect can wear a little thin, lacking the lasting attraction of a rectilinear lens