Fast Design and Refined Optics
- Two XA (extreme aspherical) elements, along with one standard aspherical element, promote high sharpness throughout the aperture range, even when working at the bright f/1.8 position.
- Aspherical elements feature superior surface precision for effective control over astigmatism, field curvature, coma, distortion and other spherical aberrations for highly accurate rendering and low distortion.
- The combination of several aspherical elements, along with sophisticated focusing motors, promotes a truly compact and lightweight design, especially for such an ultra-wide focal length.
- One Super ED element and two extra-low dispersion elements are featured in the lens design and help to reduce chromatic aberrations and color fringing for improved clarity and color neutrality.
- Nano AR Coating II has been applied to reduce surface reflections, flare, and ghosting for increased contrast and color rendering in strong lighting conditions. This updated coating is better suited for larger, curved elements and is especially adept at minimizing internal reflections.
Excels in Low-Light Conditions
- Rare for an ultra-wide, the f/1.8 maximum aperture is a useful asset for working in low-light conditions, such as for astrophotography applications and when making timelapses where shorter shutter speeds are required.
- The optical design has been optimized for shooting wide open; the integrated high-curvature XA elements minimize sagittal flare for cleaner, more accurate nighttime sky and point light source rendering.
Fast and Precise Focusing
- Internal focusing design offers more responsive focusing performance and maintains a consistent overall lens length during operation.
- Minimum focusing distance of 9.8" suits making dynamic close-up images.
- Despite its ultra-wide field of view, the close minimum focusing distance and bright maximum aperture enable creating shallow depth of field imagery characterized by a strong close-up subject and a soft background.
- Physical aperture ring can be de-clicked for smooth, silent aperture switching to benefit video applications. The ring also incorporates a locking "A" position for use in automated exposure modes.
- A focus hold button is present on the lens barrel for intuitive tactile control and rapid access to select programmable settings.
- Integrated petal-shaped lens hood helps to block stray light from causing lens flare and also affords some physical protection to the front element.
- Filter holder is incorporated at the rear of the lens, within the lens mount, and accepts cut gel filters and a filter cutting template is included.
- Dust- and moisture-sealed design better permits working in inclement conditions and rubberized control rings benefit handling in colder temperatures.
- Fluorine-coated front and rear elements resist dust, moisture, and fingerprints and are easy to clean.