The Sigma 18-35mm f/1.8 DC HSM is the worldu2019s first zoom lens with an f/1.8 maximum aperture, but itu2019s not as expensive as you might think. Richard Sibley and Andrew Sydenham compare the lens with the Canonu2019s premium EF 16-35mm f/2.8L II and find out how good it is

Specification: Sigma 18-35mm f/1.8 DC HSM

RRP: £799.99
Street price: Around £650
Filter diameter: 72mm
Lens elements: 17
Groups: 12
Diaphragm blades: 9
Aperture: f/1.8-16
Minimum focus: 28cm/11in
Length: 121mm
Diameter: 78mm
Weight: 810g
Lens mount: Canon EF, Nikon F, Sigma, Sony A, Pentax K

Sigma 18-35mm f/1.8 DC HSM – 18mm

Chart analysis

Tested on a Canon EOS 7D

Set to f/4 at its 18mm focal length, which is 2 stops down from maximum aperture, the performance of the Sigma 18-35mm lens is extremely sharp. At MTF 50% the resolution is around 1200lp/ph. Like the Canon lens, the Sigma 18-35mm has a slightly wavy vignetting shading graph, probably due to the complexity of all the lens construction being pushed to the limit at this short focal length. However, the actual shading is minimal, with only around 0.1EV difference in exposure.
Looking at the distortion the Sigma lens is almost identical the the Canon lens at this focal length.

Sigma 18-35mm f/1.8 DC HSM – 24mm

Chart analysis

Tested on a Canon EOS 7D

Like the Canon lens, the wave of the vignetting has smoothed out in the Sigma lens. However, there is still around 0.1EV darkening at the very edges.

There is a drop in the amount of detail the lens can resolve with the MTF 50% figure reduced to around 1000lp/ph, which is still better than the performance of the Canon 16-35mm lens. It is worth noting that there is only a slight difference between using the lens at f/1.8 and f/4, as the dark blue and red lines of the graph indicate.

Sigma 18-35mm f/1.8 DC HSM – 35mm

Chart analysis

Tested on a Canon EOS 7D

Like the Canon lens, pincushion distortion of the Sigma lens is present at this focal length, and once again there is fractionally less vignetting than at the 24mm setting. Resolution is still very high and, again, with the lens aperture set to f/1.8 or f/4, the resolution is greater than 1000lp/ph at MTF 50%, which is very impressive. What is even more pleasing is how close all the lines are, showing very little difference between apertures at the centre and edges. This is clearly as a result of the centre areas of the lens being using to create the image at this focal length. Overall, performance is extremely good. 

Score: 4 out of 5

  1. 1. Introduction
  2. 2. Page 2
  3. 3. Specification: Sigma 18-35mm f/1.8 DC HSM
  4. 4. Specification: Canon EF 16-35mm f/2.8L II
  5. 5. Page 5
  6. 6. Page 6
Page 3 of 6 - Show Full List
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