Sigma 17-35mm F2.8-4 EX DG HSM review - an old, cheap, and... great wide-angle lens!

First of all, let’s take a look at the results for the Sigma lens by itself:

Sigma 17-35mm F2.8-4 EX DG Aspherical HSM Canon mounted on a Canon EOS 1Ds Mark III

With a DxO Mark Score of 20, this wide-angle zoom is indeed a good-quality lens.

Strong points	Weak points
Good sharpness	Significant vignetting at maximum aperture
Good correction of chromatic aberration	Rather weak transmission
Very reasonable price
An acceptable weight

Comparison

Sigma 17-35mm F2.8-4 EX DG Aspherical HSM Canon vs Canon EF 16-35mm f/2.8L II USM mounted on a Canon EOS 1Ds Mark III

Both lenses achieve the same DxOMark overall score of 20. When looking at the results a bit more closely, the Sigma’s quality seems actually somewhat lower (see also the DxOMark score map).

In fact, the Sigma’s performance drops off a bit for the greatest focal lengths (starting at 28 mm), due to the fact that the Sigma doesn’t maintain a constant f/2.8. To compensate for the loss of brightness, one must augment the ISO sensitivity – and consequently, noise goes up as well.

Sigma 17-35mm F2.8-4 EX DG Aspherical HSM Canon

The advantages	The disadvantages
Homogenous sharpness in the field at maximum aperture	An aperture that varies depending on the focal length
Good correction of chromatic aberrations	Very heterogenous optical quality
A truly affordable lens in terms of price

Canon EF 16-35mm f/2.8L II USM

The advantages	The disadvantages
Homogenous optical quality	Good sharpness only in the first third of the field
With a constant aperture, the Canon is brighter	Very strong chromatic aberrations chromatiques in the corners at 16mm
	High price

Conclusion

The Sigma 17-35mm F2.8-4 EX DG Aspherical HSM Canon is a very good lens for the price. While each lens has its strong and weak points, the Sigma quite frankly manages to hold its own against its pricier Canon rival.