The Sigma 24-70mm F2.8 DG HSM OS Art is a premium workhorse zoom lens designed for the latest high megapixel DSLRs. A constant aperture of 2.8 through the zoom range makes this a highly versatile tool and a brand new Optical Stabilization (OS) system helps compensate for camera shake. Though a common focal length, the Sigma 24-70mm Art brings a new level of usability and durability featuring a rugged metal barrel and an emphasis on image quality. Building off the experience from the 12-24mm Art, the aspherical elements used in the 24-70mm F2.8 OS Art undergo a highly precise level of polishing, producing elements thicker in the center than on the edges. This process creates stunning image quality and beautiful circular bokeh.
The performance and functionality that pros in all fields require
What photographers demand from the 24-70mm F2.8 specification is much more than outstanding image quality. They want all the features that make this a go-to lens for a wide range of photographic opportunities, including optical design ideal for the latest ultra-high-megapixel digital cameras, hypersonic motor (HSM) for high-speed autofocus, optical stabilizer (OS) with powerful stabilization effect, dust- and splash-proof mount with rubber sealing, and a metal barrel for a stable, rigid feel. This all-new 24-70mm F2.8 lens from SIGMA delivers the performance and functionality that help pros succeed in news, nature, and many other fields of photography.
Art line delivers high-level artistic expression
SIGMA is organizing all its interchangeable lenses into three product lines: Contemporary, Art, and Sports, each with a distinctive concept. Designed with a focus on sophisticated optical performance and abundant expressive power, our Art line lenses deliver high-level artistic expression. Offering astonishing rendering performance that meets the highest standard, they are perfect for landscapes, portraits, still-lifes, close-ups, and casual snaps. They are made for the kind of photography that unleashes the inner artist. A powerful ally in every genre of photography, SIGMA's Art line lenses excel both in the studio for formal works and outdoors for impressive shots of architecture, starry skies, and many other scenes.
The large-diameter standard zoom ideal for today’s ultra-high-megapixel digital cameras
SIGMA’s Art line: a focus on high resolution
To fulfill the uncompromising image quality standard of the Art line, this lens features a power distribution that has been optimized in exacting detail. This is the lens for those who desire consistent resolution at maximum F2.8 brightness or lower and complete control of the beautiful bokeh effect.
Outstanding optical performance
Three SLD glass lens elements and four aspherical lens elements help minimize optical aberrations. To ensure outstanding image quality from the center to the edges of the photograph, the optical system minimizes coma, which causes points of light to streak, and transverse chromatic aberration, which cannot be corrected by adjusting the aperture. The optical system also minimizes distortion, which can be particularly evident in wide-angle shots, resulting in excellent optical performance throughout the zoom range.
Incorporating advanced aspherical lens processing technology
Aspherical lenses necessitate refined expertise in the design and manufacturing of advanced, high-performance lenses. SIGMA’s representative products to feature this technology were the SIGMA 12-24mm F4 DG HSM | Art and SIGMA 14mm F1.8 DG HSM | Art, which both incorporated large ⌀80mm aspherical lenses as their front lens element.
Building on the success of these predecessors, the SIGMA 24-70mm F2.8 DG OS HSM | Art incorporates an aspherical lens element that helps achieve extremely high resolution. This element is much thicker at the center than the edges, and forming its unusual shape is a feat of manufacturing technology. Moreover, SIGMA processes the surface of this aspherical lens element with ultra-precise tolerances that are measured in hundredths of a micrometer. This extremely fine surface allows the SIGMA 24-70mm F2.8 DG OS HSM | Art to deliver a very natural and smooth bokeh effect, without the visible concentric rings that afflict typical aspherical lens elements.
A 24-70mm F2.8 lens that meets the high standards of the Art line
SIGMA has continuously pioneered 24-70mm F2.8 lenses that are a step ahead of the times. The first model of this specification, SIGMA 24-70mm F2.8 EX DG ASPHERICAL DF, launched in 2001. Representing the fourth generation of the family, the new SIGMA 24-70mm F2.8 DG OS HSM | Art accomplishes a challenging feat in optical design: incorporating optical stabilizer functionality in a large-diameter standard zoom. By leveraging all of its design and manufacturing expertise, SIGMA has ensured that this new lens fulfills the uncompromising requirements of the Art line for image and build quality.
Bokeh that is a cut above
At wide-open aperture, this lens offers outstanding photographic expression. The area in focus is extremely sharp, while the background exhibits a beautiful bokeh effect with only slight spherical aberration. Since large-diameter zoom lenses are often used at wide-open aperture, SIGMA has paid close attention to the shape of the bokeh, aiming for perfect circularity.
Exclusive low-dispersion glass
The degree to which light is refracted by glass depends on the light's wavelength. This fact causes different colors of light to focus at slightly different points. The result is chromatic aberration, the color fringing that is particularly noticeable in telephoto lenses. Most chromatic aberration can be removed by combining a high-refractivity convex lens element with a low-refractivity concave element. Yet residual chromatic aberration known as “secondary spectrum” may still remain. To minimize this secondary spectrum, which can be a serious issue with conventional lenses, SIGMA lenses feature up to three types of exclusive low-dispersion glass offering superior performance: ELD (Extraordinary Low Dispersion), SLD (Special Low Dispersion) and FLD (“F” Low Dispersion). In particular, FLD glass offers ultra-low dispersion in combination with high transmittance and the anomalous dispersion characteristics of fluorite. Meticulous deployment of these types of exclusive low-dispersion glass and optimization of power distribution gives SIGMA lenses superlative image rendition undiminished by residual chromatic aberration.
Designed to minimize flare and ghosting
From the start of the design process, SIGMA measured flare and ghosting to establish an optical design that is resistant to strong incidental light sources such as backlight. At the prototyping stage, SIGMA used not only simulations but actual photographic experiments to assess flare and ghosting under multiple criteria, identify the causes of these issues under a wide range of situations, and take measures to mitigate them. In addition, SIGMA’s Super Multi-Layer Coating helps further reduce flare and ghosting and provide sharp, high-contrast images even in backlit conditions.
OS and other features for success on any shoot
OS functionality, newly designed HSM, dust/splash-proof construction, electromagnetic aperture control (for Nikon), and more
This lens has all the features and functions photographers need to be successful on a wide variety of shoots. In addition to outstanding image quality, this lens offers autofocus, construction that minimizes the incursion of dust and debris, an optical stabilizer (OS) function, and more. To make this lens as easy to use as possible by photographers in all fields, it features not only SIGMA’s most advanced mechanical systems but also the company’s latest software.
Incorporating the OS function for success on any shoot
Designed for use in a wide variety of situations, the optical stabilizer (OS) offers a powerful stabilization effect of 4 stops*.
* Based on CIPA guidelines. Measured at the telephoto setting on a camera with a 35mm full-size image sensor.
Lens barrel designed for high rigidity
Since large-diameter standard zoom lenses tend to serve as a go-to lens and see frequent use, the SIGMA 24-70mm F2.8 DG OS HSM | Art is designed to stand up to the challenging shooting environments that pros encounter. To this end, the lens barrel contains a large amount of metal, while the external moving parts feature thermally stable composite (TSC), which is resistant to thermal expansion and contraction. This structure contributes not only to the outstanding optical performance of the lens but also to its high rigidity and confidence-inspiring build quality.
Newly designed HSM for fast AF performance
The newly designed hypersonic motor (HSM) offers 1.3 times the torque of its predecessor. Even at low speeds, it offers exceptionally stable performance.
Nikon electromagnetic diaphragm mechanism included
The Nikon mount version of this lens includes an electromagnetic diaphragm mechanism that allows it to receive the appropriate signals from the camera body. This feature ensures precision diaphragm control and stable Auto Exposure (AE) performance during continuous shooting.
* Functionality may be limited on some camera bodies.
Fast AF with full-time manual focus
Full-time manual focus function allows the lens to be switched to manual focus simply by rotating the focus ring.
Note: The operation of full-time MF may vary based on mount type.
Mount with dust- and splash-proof design
Since the area of the lens most vulnerable to dust and other foreign bodies is the mount, rubber sealing* helps provide peace of mind. In addition, the front lens element features a water- and oil-repellant coating that helps the lens perform well in the rain, near water, and in other challenging conditions.
High-precision, rugged brass bayonet mount
The brass mount combines high precision with rugged construction. Its treated surfaces and enhanced strength contribute to the exceptional durability of the lens.
SIGMA USB DOCK makes customization and flexible adjustment possible
SIGMA USB DOCK for SIGMA GLOBAL VISION lenses (optional)
With the optional SIGMA USB DOCK, you can update your lens firmware and adjust the focus position and other settings. Simply connect the lens to the SIGMA USB DOCK and the dock to a computer to use the dedicated SIGMA Optimization Pro software and perform various types of customization and adjustment.
New SIGMA Global Vision product lines are setting new benchmarks for image quality
Evaluation with SIGMA's own MTF measuring system: A1
We used to measure lens performance with a Modulation Transfer Function (MTF) measuring system using conventional sensors. However, we have developed our own proprietary MTF measuring system (A1)* using 46-megapixel Foveon direct image sensors. Even previously undetectable high-frequency details are now within the scope of our quality control inspections. All SIGMA 24-70mm F2.8 DG OS HSM | Art lenses are checked using this A1 system before they are shipped.
*A1：Aizu １
46-megapixel Foveon direct image sensor
The 46 effective megapixel (4,800 × 3,200 × 3 layers) and 44 recording megapixel (4,704 × 3,136 × 3 layers) 23.5 × 15.7mm APS-C X3 direct image sensor captures all primary RGB colors at each and every pixel location, ensuring the capture of full and complete color. Using three silicon-embedded layers of photo detectors, stacked vertically to take advantage of silicon's ability to absorb red, green and blue light at different respective depths, it efficiently reproduces color more accurately, and offers sharper resolution, pixel for pixel, than any conventional image sensor. Since color moiré is not generated, the use of a low-pass filter is not required, meaning light and color, generated by the 46-megapixel APS-C X3 direct image sensor is captured with a three-dimensional feel.
Ultra-high precision and quality—all made in Japan
With only a few minor exceptions, all of SIGMA's manufacturing, including molds and parts, takes place under a single integrated production system in Japan. We are now one of the very few manufacturers whose products are truly made in Japan. We like to think our products are somehow imbued with the essence of our homeland, blessed as it is with clean air and water, and focused, hard-working people. We pride ourselves on the authentic quality of SIGMA products, born of a marriage between highly attuned expertise and intelligent, advanced technology. Our sophisticated products have satisfied professionals and lovers of photography all over the world because our manufacturing is based on genuine craftsmanship, underpinned by the passion and pride of our experts.
