The lens construction consists of two SLD glass elements and three aspherical lens elements. Aspherical lenses are used for both the front and rear optics. This not only keeps the size of the lens compact but also helps with correcting lens aberrations. As a result, the lens features a 55mm filter thread (which is smaller than comparable lenses of similar focal lengths) which makes it easy to change filters between Sigma I series lenses that share the same filter size.* Its construction also helps minimize flare and ghosting that is commonly found in ultra-wide-angle lenses, creating clear images in any environment. This is a lens with truly modern performance, thanks to the advanced processing and production technologies at Sigma's only production facility in Aizu.

A highlight of using the 17mm is the impressive minimum focusing distance of 12cm. Capture close-up macro style images in remarkable detail with expansive backgrounds. It is also suitable for selfies and vlogging, where items need to be shown at an arms-reach. A quiet, high-speed stepping motor drives the AF delivering fast and accurate results in both stills and video.

All I series lenses have an all-metal construction. The precision-cut aluminum parts not only give the barrel a sleek, stylish finish, but provide superb durability that improves the quality of the entire product. Metal materials are also used in internal structures that slide with the operation ring for added robustness. These high-precision components crafted with Sigma's cutting-edge metalworking technology are also used in Sigma's Cine Lens line-up for professional cinematographers and provide a tactile, ergonomic feel that make the lens a pleasure to use. What is more with the I series is that this high build quality is condensed into a palm-sized lens body. The Sigma 17mm F4 DG | Contemporary is one of the smallest in the series. Combine with multiple I series lenses to create a remarkably compact shooting system that is lightweight and small in size.

I series lenses are accompanied by a dedicated magnetic metal lens cap, in addition to a normal plastic cap. This dedicated metal cap clips to the front surface of the lens magnetically. It is no exaggeration to say that this meticulously crafted cap represents the finishing touch for the I series.

Inner focus system

To increase stability, this lens configuration uses movable internal lens elements that adjust focus without changing the length of the lens barrel.

Compatible with Lens Aberration Correction

Matching the optical characteristics of the lens, this function performs in-camera corrections of peripheral illumination, chromatic aberrations, distortion, and more, to further enhance image quality.

*Function available on supported cameras only. Available corrections or auto correction functionality may vary depending on the camera model.
*On cameras where lens aberration correction is controlled with 'ON' or 'OFF' in the camera menu, please set all aberration correction functions to 'ON' (AUTO).

Super Multi-Layer Coating

Sigma's own Super Multi-Layer Coating suppresses flare and ghosting by preventing reflections with in the lens. All lenses in the current Sigma range feature this original technology. In digital cameras, flare and ghosting may also be caused by reflections between the image sensor and lens surfaces. Here too, Sigma's Super Multi-Layer Coating is highly effective, assuring images of outstanding contrast.

Aperture ring

Aperture ring, designed to help users work intuitively.

Focus Mode Switch

Using this switch, it is possible to switch the focus mode between AF and MF.

Mount with Dust and Splash Resistant Structure

The lens mount incorporates rubber sealing to protect the mount from dust and water drops.

Others

• Rounded diaphragm
• Compatible with high-speed autofocus
• Compatible with AF Assist (Sony E-mount only)
• Compatible with Sigma USB DOCK UD-11 (sold separately / L-Mount only)
• High-precision, durable brass bayonet mount
• Support DMF and AF+MF
• Designed to minimize flare and ghosting
• Every single lens undergoes Sigma's proprietary MTF measuring system
• Magnetic metal lens cap
• "Made in Aizu, Japan" craftsmanship

Lens Construction  9 elements in 8 groups

Accessory Camera Wall  No

Edition Number  C023

Sensor Size  Full Frame

Angle Of View  103.7°

Number of Diaphagm blades  7 (rounded diaphragm)

Minimum Aperture  F22

Minimum Focusing Distance  12 cm / 4.8 in.

Maximum Magnification Ratio  1:3.6

Filter Size  55mm

Dimensions  Sony E-Mount: 64mm x 50.8mm / 2.5 in. x 2.0 in.

Weight  Sony E-Mount: 220g / 7.8 oz.