Sigma 24-70mm f/2.8 DG DN Zoom Lens for Leica L

Description

the following was taken from sigmas website
Features
Best-in-class optical performance
The F2.8 Art zoom flagship zoom lens series is developed primarily to achieve superior optical performance. As extra-low dispersion glass materials, six sheets of “F” low dispersion (FLD) glass and two sheets of special low dispersion (SLD) glass are lavishly employed while taking advantage of an optical design dedicated for mirrorless lenses. By employing three aspheric lenses, this zoom lens thoroughly subdues aberrations such as axial chromatic aberration or sagittal coma aberration, which are difficult to correct in post-processing, tailors the resolution and achieves uniformity and superior optical performance from the center to the periphery throughout the zoom range.
The mirrorless camera-dedicated design successfully contributes to reduction in the lens size and weight.
Ensuring compatibility with
the latest
full-frame
mirrorless
camera bodies
The SIGMA 24–70mm F2.8 DG DN ensures compatibility with various types of the latest full-frame mirrorless camera bodies tailored for L-Mount and Sony E-Mount so as to be capable of exerting the best performance under any photographic circumstances, assuming that professional or advanced amateur photographers use it. To the AFL button, for example, various functions can be assigned from a camera body*, which enhance the operability while photographing. Employing a stepping motor and the latest algorithm successfully establishes a good balance between acceleration and quietness of the AF drive. This enables stress-free focusing. Furthermore, this lens is compatible with the Eye-Detection AF used more frequently in mirrorless cameras, which is capable of high-precision focusing at the time of portrait photography.
* This has a constraint depending on camera bodies used.
Adaptable to various uses and photographic environments
In consideration of shooting under challenging shooting conditions, the dust and splash resistant structure* and water- and oil-repellent coating are adopted. In addition, a variety of functions, such as an AFL button that can assign various functions to the lens barrel, a zoom lock switch that is unlocked by zoom operation, a nice touch AF / MF switch, are provided.
* Although this construction allows the lens to be used in light rain, it is not the same as being waterproof.
Basic functions
1
AF/MF switch
2
AFL button
3
Zoom lock switch
SIGMA’s unique coating technology Nano Porous Coating
The super multi-layer coating is combined with SIGMA’s unique coating technology “NPC (Nano Porous Coating)”. The lens has been designed to be less susceptible to strong incident light such as backlight.
“NPC (Nano Porous Coating)” incorporates porous silica as the coating material. The porous silica layer has nano-sized holes with air inside. Having holes of this size enables a large reduction in the refractive index, allowing the reflectance to be lowered more than conventional anti-reflective coatings. As a result, reflected light causing flares and ghosting is sharply reduced, achieving clear image quality.
About the shortest shooting distance
The minimum focusing distance is 18 cm at the wide-angle end. This allows you to come closer to a subject than the end of a hood to take photographs*. The maximum magnifications are 1:2.9 at the wide-angle end and 1:4.5 at the telephoto end, which provides a wider range of expression by close-up photography.
* Be extremely careful that the front lens element does not hit the subject when photographing. Remove the lens hood from the camera body before use when photographing at the minimum focusing distance at the wide-angle end.
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Other features
Designed to minimize flare and ghosting
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. In addition to Super Multi-Layer Coating, Nano Porous Coating is employed. These coatings reduces flare and ghosting to help photographers produce sharp and high contrast images even in backlit conditions.
Rounded diaphragm
(11-blade)
The 11-blade rounded diaphragm creates an attractive blur in the out-of-focus areas of the image.
Hood with lock
Features a hood with lock to prevent dropping the hood.
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.