Offering a super-fast maximum aperture of f/1.8 straight through the focal range, is this a zoom you need in your bag?
When sigma announced that it was developing the world’s first zoom lens to feature a super-fast, fixed aperture of f/1.8 throughout the focal length range, the news certainly turned some heads in the photography world. Offering such a wide maximum aperture across a zoom range is something that, up until now, was unheard of within D-SLR photography. The new 18-35mm f/1.8 lens is part of Sigma’s range of ‘Art’ lenses, which is denoted by the shiny ‘A’ badge on its barrel.
Specifically designed for D-SLRs with an APS-C sized sensor, its 18-35mm focal range translates to 28.8-56mm when mounted on our Canon 600D test camera, which has a 1.6x crop factor, or 27-52.5mm when married to a D-SLR with a 1.5x crop. With a zoom range spanning from wide-angle to a ‘standard’ view, the Sigma 18-35mm is a versatile lens that’s designed for shooting landscapes and half-length portraits with a single twist of the zoom ring. That said, with the president of Sigma Corporation America explaining that creating such a lens was both “technologically and optically challenging”, is this revolutionary new glass really able to deliver top quality results? Well, we’ve managed to get hold of a review sample to find out...
Features & build
The lens mount is made from a robust brass construction, which is more durable than plastic mounts, and is available in a choice of Sigma, Canon, Nikon, Sony and Pentax fits. Inside, the lens is constructed from a total of 17 elements in 12 groups, which include five Special Low Dispersion (SLD) glass elements and four Glassmold Aspherical lenses with Super Multi-Layer Coatings to help reduce flare, ghosting and aberrations. The aperture diaphragm is constructed from nine rounded blades for a pleasing bokeh in out-of-focus areas, with the aperture range spanning from f/1.8 to f/16.
Placed on the scales, the lens weighs in at a rather hefty 810g, with the barrel made from Thermally Stable Composite (TSC), which Sigma claims to have minimal thermal shrinkage combined with exceptional hardness and 25% greater elasticity than the more common polycarbonate casings, all adding up to a very robust feel. In total, the lens measures 121mm long, and thanks to an internal focus system, the barrel length and front element stay put when focusing and zooming – useful when using filters like ND grads and polarisers – and it has a large 72mm filter thread.
As the ‘HSM’ portion of its name suggests, the lens features Sigma’s Hyper Sonic Motor, which works by using ultrasonic waves to drive the AF motor, allowing faster and quieter autofocusing. There’s also a MF/AF switch on the side of the lens to allow manual override, should you wish to focus your pictures manually instead.
It’s also worth mentioning that in the box, the Sigma 18-35mm comes packaged with a plastic, petal type lens hood and a thick padded carry case to protect it from scuffs and scratches – both being welcome additions.
Performance & Handling
In terms of aesthetics, the Sigma 18-35mm looks fantastic; its matte black paintwork teamed with silver and white detailing resembles that of a ‘Stealth Fighter’ jet and it just oozes high build quality. The zoom and focus rings are both easily located when your eye’s to the viewfinder and both operate with a smooth action. Zooming from 18mm to 35mm is possible in just 1/8th of a turn, while focusing is aided by a focus distance window on the top of the barrel. The MF/AF switch has been placed on a protruding section between the two rings, which makes it easy to locate, though the switch itself proved a little stiff and fiddly to use when concentrating on the viewfinder.
Mounted to our Canon EOS 600D, the 18-35mm felt a little front-heavy with its not inconsiderable weight of 810g, though thanks to the internal zoom and focusing mechanisms, the balance was consistent throughout the zoom range.
During testing the AF was quick and responsive with little signs of hunting. The Hyper Sonic Motor was quiet in operation, with only a subtle whirring, and the lens put in a very solid performance.
Value for Money
If you’re looking for a fast zoom, then it’s also worth considering the Sigma 17-50mm f/2.8 EX DC OS HSM at £320, as it’s less than half the price and gives more reach. That said, its f/2.8 aperture doesn’t match the super-fast f/1.8 of the 18-35mm, so if you want the creative aperture control normally only found in primes, this unique lens may be the one you’ve been waiting for.
Credit must be given to Sigma for taking the plunge and being the first to pull off this optical feat. Despite being a touch heavy – especially for a lens intended for smaller APS-C format D-SLRs – the 18-35mm impressed us in almost all areas of testing. So, if you’re in the market for a well-built zoom that offers impressive image quality and great control for shallow depth-of-field effects, it’s a great choice – provided you can stomach the £650 pricetag.
- Street price: £549 (As of July 2016)
- Focal length: 18-35mm
- Sensor format: APS-C
- Lens construction: 17 elements in 12 groups
- Apeture blades: 9
- Max aperture: f/1.8
- Min aperture: f/16
- Min focus distance: 28cm
- Filter Thread: 72mm
- Mounts: Canon, Nikon, Pentax, Sigma, Sony
- Dimensions: 78x121mm
- Weight: 810g
- Visit: www.sigma-imaging-uk.com
This review was first published in the October 2013 issue of Digital Photo - download back issues here.