A review of the Sigma 24-70mm F2.8 DG OS HSM Art
Sigdmin

Introduction
There is no lens manufacturer that has done a better job than Sigma at combining incredibly build quality with an affordable price tag. With their introduction of the Art Series in 2013, Sigma has gained many new fans including myself! The spectacular Sigma 35mm Art and the Sigma 85mm Art are the lenses that open peoples eyes to the incredible quality of the sigma range. The Sigma 24-70mm F2.8 DG OS HSM Art is Sigma’s new standard zoom lens, and I was very excited to get my hands on this long awaited addition to the Art family. The Sigma 24-70mm Art is an important addition to Sigma’s high-performance Art series, with an extremely versatile focal length. Sigma has consistently delivered great lenses when it comes to the Art lineup, and as a result I am always itching to get another Art lens in my bag.
The Lens
When picking up the Sigma 24-70mm Art, you’ll be reminded quickly of the build quality that has come as a tradition with Sigma Art lens. Weighing in at just over 1kg. The weight is dense as the lens itself is actually shorter than its Canon and Nikon competitors. When handling the lens, there are no doubts that it is of professional caliber, and can manage the abuse that wildlife and travel photographers like myself tend to put our equipment through. The build quality is excellent, given the comparatively affordable price tag. The lens is constructed with a plastic shell with a mixture of metallic parts and thermally stable composite (TSC) inside. It also incorporates a brass bayonet mount for durability. The optical elements are made of high-grade glass. Focusing is internal and manual focusing is possible when set via the focus switch on the lens barrel, with constant manual focus override available at any time when rotating the focus ring. Optically the lens is constructed in 19 elements in 14 groups. This includes three Super Low Dispersion and 4 Aspheric elements. The diaphragm comprised of 9 rounded blades.
The zoom action on the lens is very smooth and the near silent OS and focus motor makes the lens feel extremely well designed. The lens is moisture resistant which is great for use in harsh environments. The zoom ring is wide and grips well which feels very precise, and combined with the weight feels solid in your hand . The lens feels very well engineered, and is a clear result of all Sigma lenses being made solely in Japan. The lens is also compatible with the Sigma USB dock which helps make adjustments and upgrades to customise the lens to the most convenient setting for each project.
Focusing
The Sigma 24-70mm offers built-in optical image stabilisation, combined with a Hyper Sonic Motor (HSM) for fast and quiet autofocusing. The optical stabilisation works exceptionally well, offering up to three stops of stabilisation. I found that when it comes to auto-focusing, the Sigma 24-70mm Art was both accurate and impressively fast, with next to no focus “hunting” in most light conditions. The lens accurately focuses throughout the zoom.
Image quality
Image quality is undoubtedly the most important aspect of the review, and I am pleased to say that images are centrally pin sharp throughout the zoom. At 24mm the central sharpness is excellent from f/2.8 all the way through to f/8. At 70mm the lens has really good sharpness from f/2.8 to f/8, but the edges are just slightly softer at 70mm, but this can be expected with a zoom lens. With subjects in the centre of my images this proved to actually give an added bokeh effect making the image pop. The lens has beautiful colour rendition and handles contrasting light extremely well. At its widest focal length 24mm, the lens shows no noticeable distortion and this has become a great selling point for me with the 10-20mm and the 8-16mm Art lenses. One of this lens’s greatest selling points is its visually stunning bokeh for a zoom lens. Bokeh is a word used for the out of focus areas of a photograph. While the visual look of bokeh is always subjective to the photographer, Sigma has employed an iris diaphragm with nine rounded blades, which in my opinion has resulted in a very beautiful soft look. The lens has very little vignetting and the overall image quality really is beautiful. Flare does not seem to be a problem with the lens shooting into the sun, despite the complexity of the optics of this lens. Details such as almost non existent chromatic aberration make the 24-70mm a great lens, it also means without much processing you are able to create visually beautiful images.
Final verdict
The Sigma 24-70mm f2.8 OS Art is a worthy upgrade over its decade-old predecessor. It has very good image stabilisation and is shorter, cheaper, faster, and creates beautiful bokeh. In short, 24-70mm is a fantastic focal length and makes for an exceptional all-round lens to have in any camera bag. The build quality which has come standard with the Art range is incredible. With minimal distortion, Chromatic Aberration, and flare, the lens really is a great allrounder. No doubt if you are looking for a pro-grade 24-70mm lens, you will be impressed with the quality and value for money that this lens provides.

Sigma 24-70mm Art Pros

  • Very good build quality.
  • Central sharpness throughout the zoom is good.
  • Distortion and Chromatic Aberration is minimal.
  • The bokeh of this lens is truly beautiful for a 24-70mm.

 
Sigma 24-70mm Art Cons

  • Although it is dust and splash proof, the lens is not weather sealed.
  • Slightly on the heavy side.
  • Slightly soft on the edges at 70mm

All images photographed on a Canon 7D Mark 2
William Steel, Sigma Ambassador