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Lens review

Sigma A 12-24 mm f/4 DG HSM

23 October 2016
Szymon Starczewski

3. Build quality

The following chart compares the tested model to its two predecessors and a rival from the Canon company. It’s obvious that the new Sigma and Canon are physically the heaviest and the biggest instruments in this group; still it’s the Canon which boasts of the widest focal range. The Sigma tries to offer the best minimum focusing distance for a change as its range starts from 20 cm. In newer lenses you get an aperture with nine blades; in the older ones the aperture had just six of them.

In the photo below the Sigma A 12–24 mm f/4 DG HSM is positioned next to the Sigma A 35 mm f/1.4 DG HSM.

Sigma A 12-24 mm f/4 DG HSM - Build quality

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The tested lens begins with a metal mount, which surrounds contacts and a rear element, 24 mm in diameter, and a rubber gasket . The rear element is positioned on the same level as the mount at 12 mm and it hides inside the casing about 2 cm deep when you pass to 24 mm. During that movement a quite huge slit appears in the rear tube and you can glimpse some internal parts of the lens through it. Still the area inside the mount is blackened, ribbed and matted very well.

Sigma A 12-24 mm f/4 DG HSM - Build quality

The proper body of the lens starts with a smooth, black ring made of metal on which you can find a white dot, making the alignment with a camera easier, and an inscription “016”. Further on you see a zoom ring. It is 20 mm wide and most of its surface is covered by rubberized ribs above which you see focal length marks at 12, 14, 16, 18, 20 and 24 mm. The ring is properly damped, allowing you smooth movements and precise settings.

Sigma A 12-24 mm f/4 DG HSM - Build quality


The next fragment of the barrel doesn’t move and it features the name and the parameters of the lens; above them there is a distance scale behind a window, expressed in feet and meters. On the left side of the scale there is an “A” letter meaning the lens was classified as an “Art” group device and a focusing mechanism mode switch (AF/MF FOCUS).

Sigma A 12-24 mm f/4 DG HSM - Build quality


Then the barrel gets noticeably larger and that part boasts a manual focus ring, as wide as 19 mm. Most of its surface is covered by rubber ribbing. The ring moves smoothly and is well damped; running through its whole distance scale takes a turn through an angle of about 100 degrees.

Sigma A 12-24 mm f/4 DG HSM - Build quality


Behind the manual focus ring there is an immobile part of the casing with an inscription “MADE IN JAPAN” which turns smoothly into a build-in lens hood.

The front element is distinctly convex and really huge. Its diameter amounts to as much as 80 mm. It is the most extended at 12 mm and at about 22 mm it hides inside the barrel the deepest.

Sigma A 12-24 mm f/4 DG HSM - Build quality

What’s interesting, the new model is less optically complex than its predecessor so the Sigma 12-24 mm f/4.5-5.6 II DG HSM which featured 17 elements positioned in 13 groups. The new, faster lens has 16 elements in 11 groups; still the number of special elements is really impressive. You get as many as five elements made of FLD glass with fluorite properties, two huge aspherical elements and one which is made of SLD glass and aspherical in the same time. Inside there is also an aperture with nine diaphragm blades that can be closed down to a value of f/22.

Buyers get both caps and a hard case for the lens in the box.

Sigma A 12-24 mm f/4 DG HSM - Build quality