This wide-angle zoom from Sigma was originally designed for 35mm film cameras. Is it getting long in the tooth? We take a look at how it holds up in the digital age.
- Focal Length 15-30mm
- Construction 17/13 elements/groups
- Angle of view 110.5-71.6° (Full frame view)
- Max Aperture f/3.5-4.5
- Min focus 30cm
- Filter size Rear gelatine
- Dimensions 87x132.5mm
- Weight 0.62kg
- Mount Sigma, Canon, Nikon, Minolta, Pentax
- Price (SRP) £599.99
Build and handling
This lens is large by the latest standards and has a convex, protruding front element that is protected by a fixed, petal shaped hood. The zoom ring is the closest to the camera of the two operating ring and, unusually, is the narrower of the two. It is separated from the manual focus ring by a neat distance window marked in metres and feet. Divisions of 15,17, 20, 24 and 30mm are the only other guides on the barrel. The manual focus ring has a push/pull action, which, together with the normal switching, changes the lens from manual to autofocus. The AF, although a little whiney, is fairly responsive and accurate whilst the manual method is nicely torqued and has a smooth action.
The most disconcerting thing about the lens is the protruding front element which, although protected to some extent by the fixed metal petal hood and a sleeve that fits over this to accommodate the 82mm lens cap, still seemed vulnerable. There is a filter thread on the sleeve and the good news is the sleeve does not vignette when the lens is used on a 1.6x crop camera. Provision is made for rear fitting gelatine filters and a metal template is supplied for cutting to size. Focussing and zooming does not change the physical length of the lens, although the front element does extend inside the hood when zooming to the widest setting.
In common with most zoom lenses, and indeed, lenses generally, the 15-30mm EX DG benefits from being stopped down a click or two. Remembering that the lens was developed for the full 35mm frame of film SLR’s, Sigma’s addition of their DG coating has made a noticeable difference to the lens’ usability on digital sensors and it’s useful focal range has ensured its longevity. Let down slightly by the distortion, measured at -5.05% (Barrel) at the wide end, it recovers to a negligible 0.32% (pincushion) at the longer focal length. Even so, it is a remarkable optical achievement. Chromatic aberration, the bain of the digital photographer, is kept to a minimum by the use of a moulded aspherical in the rear lens group and although not completely clear of the phenomenon it is good enough to pass most inspections.
Contrast can be classified as good with a neutral colour balance producing no casts. Flare and ghosting are reasonably well controlled, helped again by the new DG coating but, possibly due to the bulbous front element, it is possible to induce these characteristics with a strong directional torch. It did not, however, show up in general use.
The optimum aperture of the lens is around the f/8 mark when at the wider settings but shifts to f/11 by the time it reaches its longest focal length.
Just so you can see where that door is situated. The contrast with the sky did not show any CA. 21mm on Canon 20D at f/4.
Being a quirky lens makes you think (and frame things) quirkily as with this ex-lifeboat from the harbour wall! 15mm and f/5.6 on 20D.
At 15mm, this lens is wide enough, even on a cropped sensor, to just start on dramatic perspective. On a full frame camera it is very wide! Canon 20D, 1/340sec at ISO200 and f/8.
Click on each comparision photo below to view full size versions
Below is our lens test data. To find out how to use these graphs look at this article: How we test lenses
Despite this lens’s slightly older design, it still holds up well against it’s more modern competitors and for anyone contemplating a future move to full frame digital capture it is well worth a look. The focal range is useful on cropped digital sensors and it is a very wide lens on full frame. The only let down is the jiggery pokery needed to attach filter systems to the front of it but many effects can still be had with bracketing and software.
In summary, the positive points of the Sigma 15-30mm f/3.5-4.5 EX DG are:
Good focal length, compatible with full frame.
Good build quality
Built in hood and supplied with padded pouch
The negative points are:
Bulbous front element makes filter fitting a problem
A little large and heavy
Some others, even from the same manufacturer, are cheaper. (although there are bargains to be had)
Check the latest price of the Sigma 15-30mm f/3.5-4.5 EX DG here
Discuss this lens and other related lens subjects here
Test by Ian Andrews www.wildaboutkent.co.uk