Sigma 12-24mm f/4.5-5.6 II DG HSM Lens
An ultra-wide zoom lens for digital SLR cameras with both ‘full frame’ and APS-C sized sensors.As is apparent by its name, Sigma’s 12-24mm f/4.5-5.6 II DG HSM is a second-generation product that updates the popular 12-24mm f/4.5-5.6 EX DG ASP HSM that was introduced in 2002. Interestingly, its RRP is Australia is just over $250 lower than the MSRP posted on Sigma Corporation’s US website, which makes this lens excellent value for money for Australians. . . [more]
As is apparent by its name, Sigma’s 12-24mm f/4.5-5.6 II DG HSM is a second-generation product that updates the popular 12-24mm f/4.5-5.6 EX DG ASP HSM that was introduced in 2002. Interestingly, its RRP in Australia is just over $250 lower than the MSRP posted on Sigma Corporation’s US website, which makes this lens excellent value for money for Australians.
The new lens includes a couple of noteworthy exotic elements and features the latest Super Multi-Layer Coating to reduce flare and ghosting. It also comes with a Hyper Sonic Motor (HSM) drive that ensures quick and quiet autofocusing, while allowing full-time manual focus override.
The new Sigma 12-24mm f/4.55.6 II DG HSM lens. (Source: Sigma.)
Like its predecessor, this lens is designed for use with full frame digital cameras but may also be used with smaller APS-C size sensors. On cameras with 36 x 24mm sensors this lens provides the widest field-of-view currently available in a non-fisheye lens. With APS-C size sensors, it covers an effective focal length of 18-36mm with Nikon cameras or 19.2-38.4mm on Canon bodies.
The optical design is quite complex, with 17 elements in 13 groups. Revisions to the lens design include the inclusion of one Special Low Dispersion (SLD) glass element and four of the company’s new ‘F’ Low Dispersion FLD glass elements to compensate for chromatic aberrations.
Three glass moulded elements and one hybrid aspherical lens are included to minimise size and weight but this lens remains relatively large and heavy. The diagram below, sourced from Sigma Corporation’s website, shows the positions of the exotic elements but, unfortunately no colour code is provided to identify them.
At 670 grams and with a length of just over 120 mm, this lens is a sizeable handful that works best with more substantial camera bodies. A substantial part of the weight of the lens is due to the large amount of glass in the optical components.
The lack of built-in stabilisation is largely irrelevant since camera shake is seldom a problem when wide-angle lenses are used. A front cap adapter, front/rear lens cap and carrying case are included with the lens.
The front cap adapter is cylindrical and fits over the front of the lens, which has a fixed, 34 mm deep, petal-shaped lens hood. A standard clip-on cap attaches to the front of the adapter.
Build and Ergonomics
Build quality is up to the usual high standard set by Sigma and the combination of metal and high-quality plastic has resulted in a lens that feels solid and substantial. There’s a durable metal mounting plate and the focus and zoom rings feel firm enough to provide very precise adjustments.
The fixed lens hood goes some way to protect the front element of the lens, which bulges forward by roughly 5 mm, preventing filters from being fitted in the normal way. The front section of the adapter has internal threading for an 82mm filter, although this set-up can only be used with the smaller imaging areas of APS-C cameras.
Behind the lens hood is a 25 mm wide focusing ring with a 16 mm thick ribbed rubberised grip band. It rotates through approximately half a turn as you move from the closest focusing distance (0.28 metres at 12mm or 0.92 metres at 24mm) to infinity.
A distance scale is inset into the barrel just behind the focusing ring. Left of the distance scale on the same section of the lens barrel is an AF/MF slider switch.
The 28 mm wide zoom ring is just in front of the mounting plate and has a 15 mm wide ribbed grip band with slightly thicker ribbing than the focus ring. It turns through an arc covering roughly 60 degrees.
Focal lengths engraved on the leading edge of the ring line up against a white line on the trailing edge of the barrel in front. Maximum and minimum aperture settings change as focal length is adjusted, as shown in the table below.
Both zoom and focusing rings moved smoothly with no slack, allowing precise adjustments to be made. The HSM AF drive provided fast and almost noiseless focusing.
Our shooting tests were carried out with the Canon EOS 5D and EOS 40D bodies, the latter being used for the Imatest evaluations because it minimises the effect of the inherent lens distortions. Technically, it’s difficult to make such an extreme lens that is totally free of aberrations. However, our tests show Sigma has done a great job of minimising them for this type of lens.
Although edge softening was detected at wide apertures, particularly at the shortest focal length, centre-of-frame resolution was consistently above expectations between about f/5.6 and f/9 for all focal length settings. Edge sharpness had also increased at most focal lengths by around f/8. The graph below shows the results of our Imatest tests.
Lateral chromatic aberration remained consistently within the ‘low’ band for all focal length and lens aperture settings. In the graph of our Imatest test results below, the red line marks the upper edge of the ‘negligible’ CA band, while the green line represents the lower edge of the ‘moderate’ band.
Not unexpectedly, barrel distortion was easily visible in shots taken with the 12mm focal length when the lens was fitted on the Canon EOS 5D body. However, it need not prevent this lens from being used for architectural photography as it can be minimised by careful camera alignment with the subject. It was less obvious with the same focal length when the EOS 40D body (which has an APS-C sensor) was used.
The same differences were also found at the 24mm focal length, where slight pincushion distortion could be seen. Once again, the distortion was greater with the ‘full frame’ EOS 5D body than with the smaller sensor. Effectively, neither distortion could be considered significant when the lens was used on the EOS 40D.
On the ‘full frame’ camera body, the obvious barrel distortion at wider focal lengths requires care when setting up shots. You can minimise its effect by ensuring the camera back is parallel to verticals in the scene. But, the spreading effect of such a wide angle of view can’t be overcome.
Vignetting at wide apertures was much as you’d expect from such a wide-angle lens and the effect was more pronounced on the EOS 5D than the EOS 40D. It was most noticeable with the 12mm focal length and required stopping down to f/8 to suppress it sufficiently. Between 17 mm and 24mm, edge and corner darkening were less noticeable on the EOS 5D, although you must stop down to f/5.6 before they become unobtrusive.
Slight vignetting could be seen when the lens was used on the EOS 40D body when the focal length was at 12mm, although it would scarcely affect normal photography and was invisible by f/5.6. At 24mm, only traces of edge and corner darkening could be seen at f/5.6 but was gone by f/7.1.
Provided the light source wasn’t shining directly into the camera, the review lens on the EOS 40D handled backlit subjects quite well. However, with the EOS 5D, the risk of flare was much higher.
The wide angle of view makes this lens unsuitable for macro photography. Bokeh at wide apertures is as you would expect from a relatively slow, ultra-wide-angle lens.
Buy this lens if:
– You require an ultra-wide-angle lens for use on DLSR cameras with ‘full-frame’ sensors.
– You require superior build quality at an affordable price.
Don’t buy this lens if:
– You need close focusing and macro capabilities.
– You need a lens with good flatness of field.
– You like shooting with filters.
Picture angle: 122-84.1 degrees
Minimum aperture: f/22
Lens construction: 17 Elements in 13 Groups
Lens mounts: Canon, Nikon, Sigma
Diaphragm Blades: 6
Focus drive: Hyper Sonic Motor (HSM)
Minimum focus: 28 cm
Maximum magnification: 6.4x
Filter size: n.a.
Dimensions (Diameter x L): 85 x 120.2 mm
Weight: 670 grams.
Rating (out of 10):
- Build: 9.0
- Handling: 8.8
- Image quality: 8.5
- Versatility: 8.0
- OVERALL: 8.9