A large-aperture fixed focal length lens is great for achieving expressive bokeh effects and enjoying ultra-high optical performance. On the other hand, photographers often need to change the angle of view to properly capture the scene that presents itself. To solve this decades-long dilemma, Sigma proudly introduces the 18-35mm F1.8 DC HSM next-generation large-aperture APS-C format standard zoom lens for digital SLR cameras. Taking on the challenge of creating the world’s first* wide-aperture lens to offer an aperture of F1.8 throughout the zoom range, Sigma has succeeded in creating a zoom lens that offers the same high optical performance of a fixed focal length lens. These outstanding performance characteristics are especially apparent in an APS-C format camera, since it has a slightly greater depth of focus than a full-frame camera. This is a revolutionary lens that overturns preconceptions while expanding the range of photographic expression.
Designed with a focus on sophisticated optical performance and tremendous expressive power, our new Art line of lenses delivers top-level image quality. With unsurpassed expressive performance, these lenses reach the high standards demanded by photographers with an artistic, creative inclination. Along with landscapes, portraits, still-life, close-up and casual snaps, they’re perfect for the kind of photography that unleashes the inner artist. Ideal for studio photography, they offer just as much expressive scope when capturing architecture, starry skies, underwater shots and many other scenes.
To develop a large aperture zoom lens with a maximum aperture of F1.8, it was necessary to solve a variety of technical challenges. As the f-number decreases, so does the depth of focus, making it extremely difficult to minimize spherical aberration, axial chromatic aberration, astigmatism and field curvature. To minimize astigmatism across the zoom range, Sigma leveraged its extensive experience in reducing optical aberrations and designing advanced structural elements. Sigma gained this know-how when it developed such super wide angle zoom lenses as the SIGMA12-24mm F4.5-5.6 II DG HSM and SIGMA 8-16mm F4.5-5.6 DC HSM. Ongoing technological innovation at Sigma’s Aizu Factory has also contributed to further enhancements in lens production. Advanced production technologies have made possible a large-diameter molded glass aspheric lens, which teams up with SLD (Special Low Dispersion) glass elements to optimize power distribution and minimize axial chromatic and spherical aberration and field curvature. Thanks to its hard-earned knowledge of lens design and advanced lens manufacturing techniques, Sigma has succeeded in creating a lens that offers F1.8 throughout the zoom range, as well as exceptional image quality at wide open aperture.
The x-axis represents image height (distance from center of image in mm), and the y-axis represents the relative illumination at the edge of the image (with illumination at the center of the image defined as 100%). When relative illumination is low, the corners of the image appear dark, resulting in vignetting.
When photographing with point light sources such as electric lights or reflections on a body of water in the background, the rounded 9-blade diaphragm helps produce an attractive bokeh effect—even at large-aperture settings.
Zoom lenses are extremely convenient, providing a wide range of angles of view with just a twist of the zoom ring. The downside, however, is that F2.8 has been the limit of zoom lens brightness, forcing photographers to select fixed focal length lenses for brighter f-numbers. Although fixed focal lenses have been superior to zoom lenses in terms of f-number brightness and overall performance, they offer only a fixed angle of view, requiring photographers to carry several with them and change lenses as necessary. The 18-35mm F1.8 DC HSM next-generation large-aperture standard zoom lens is the world’s first* to deliver F1.8 brightness throughout the zoom range. Its bright viewfinder makes it easy to confirm focus and compose perfect shots. As compared to a F2.8 lens in the same photographic conditions, it allows the photographer to use a shutter speed that is one stop faster, reducing the influence of camera shake. In addition, the shallower depth of field makes possible a beautiful bokeh effect in the background, expanding photographic creativity. From wide open to standard apertures, this lens is highly flexible, covering the angles of view offered by multiple large-aperture, fixed focal length lenses.
There are three requirements for outstanding lenses: fine design, precise manufacturing and inspection that ensures compliance with all specifications. Sigma lenses are born of well-thought-out design concepts and sophisticated, advanced Japanese manufacturing technology; the final clincher is our lens performance evaluation. We used to measure lens performance using conventional sensors. However, we've now developed our own A1* proprietary MTF (modulation transfer function) measuring system using 46-megapixel Foveon direct image sensors. Applying this system, we check each lens in our new lines at our Aizu factory, our sole production site. Even previously undetectable high-frequency details are now within the scope of our quality control inspections, allowing us to deliver consistently high lens performance.
*A1: Aizu 1
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.
Optimizing quality with our integrated production system, Sigma is focused on making things right, with our own hands and our own techniques. We are now one of the very few manufacturers whose products are solely "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.
All lenses in Sigma’s new Art line come with a hood with a high-quality rubberized connector and feature a newly designed lens cap and AF/MF switch, and are designed for intuitive use and superior functionality. Inside, HSM (hypersonic motor) delivers high AF speed and extremely quiet performance. An enhanced algorithm offers even smoother automatic focusing. Full-time manual focus override is another key feature that leaves the artistic touches in the photographer’s hands. The brass mount combines high precision with rugged construction. Its treated surfaces and enhanced strength contribute to the exceptional durability of the lens. In both the external and internal parts, the optimized use of TSC (Thermally Stable Composite), an excellent match for metal parts, further contributes to the high-precision construction of the lens.
HSM (hypersonic motor) delivers high AF speed and extremely quiet performance. An optimized algorithm offers even smoother automatic focusing, and full-time manual focus override is another key feature.
A first for the industry, the barrel of the lens features a new TSC (Thermally Stable Composite) that offers minimal thermal shrinkage combined with exceptional hardness. It also offers 25% greater elasticity than polycarbonate. Since its thermal shrinkage is low, TSC matches well with metal parts, further contributing to the high-precision construction of the lens. TSC also makes possible slimmer forms for parts like zoom rings and scaling rings.
The brass mount combines high precision with rugged construction. Its treated surfaces and enhanced strength contribute to the exceptional durability of the lens.
The lens incorporates a rear focus system that prevents focus-dependent variation in aberration, making high-level image quality possible throughout the entire image. With their unchanging barrel length, these lenses also enhance balance and stability for the photographer. Furthermore, since the front of the lens does not rotate, polarizing filters can be used with extra convenience.
From an early stage in the lens design process, flare and ghosting have been measured to establish an optical design resistant to strong incident light sources such as backlighting. Sigma's Super Multi-Layer Coating reduces flare and ghosting to help photographers produce sharp and high contrast images even in backlit conditions. The included lens hood can be attached to block out extraneous light, which can have a negative effect on rendering performance.
For our new product lines, we have developed exclusive SIGMA Optimization Pro software that allows the user to update the lens firmware and adjust focus position and other parameters. The user will be able to connect the lens to a computer with a special SIGMA USB DOCK and use easy-to-operate on-screen controls to create personal lens specifications.
Exclusive SIGMA Optimization Pro software