Sigma 20mm f/1.4 DG HSM Art Prime Lens Sony Fit

With a focal length of 20mm and F1.4 aperture, this lens delivers outstanding large-aperture brightness and bokeh, delivering unprecedented visual experiences. Allowing the photographer to leverage the perspective provided by the wide -angle and the shallow depth of field provided by the large aperture, this lens is ideal not only for such ultra-wide-angle subjects as landscapes and starry skies, but also for snapshots in low light, indoor photography, portraits with a natural bokeh effect, and much more.

Worlds first* 20mm F1.4 lensthanks to advanced large-diameter aspherical lens manufacturing technologies
To offer an ultra-wide-angle 20mm focal length and F1.4 brightness at wide-open aperture, this lens incorporates a large double aspherical lens 59mm in diameter. Lenses of this type had been considered extremely difficult to manufacture, but SIGMA took on the challenge to realize an F1.4 ultra-wide-angle lens that fulfills the strict performance requirements of the SIGMA Art line. Delivering top performance even at wide-open aperture, this lens can be considered the culmination of SIGMA Art line.
* Among interchangeable lenses for digital cameras with 35mm full-frame image sensors (SIGMA research as of October 2015).

Minimized chromatic aberrations
This lens  features two FLD ("F" Low Dispersion)* glass and five SLD (Special Low Dispersion) glass elements to minimize transverse chromatic aberration, which is mainly visible around the edge of the image. The optimized lens power distribution helps minimize axial chromatic aberration. As a result, this lens delivers high image quality in every situation without color smearing, and its rendering performance is consistently sharp with high contrast.
* FLD glass is ultra-low-dispersion glass that offers performance of the highest level. Highly transparent, its refractive index and dispersion are extremely low as compared to conventional types of glass. These characteristics minimize residual chromatic aberration (secondary spectrum), which cannot be corrected by ordinary optical glass, while helping to produce sharp, high-contrast images.

Minimized distortion 
Distortion is a common issue in wide-angle lenses, and it is not possible to correct it simply by changing the aperture value. For this reason, a lens must be designed from the start to minimize this issue. By adjusting the incidence angle of light starting with the first lens element and incorporating optimally positioned aspherical glass elements, the SIGMA 20mm F1.4 DG HSM | Art lens minimizes distortion throughout the entire image.

Designed to minimize flare and ghosting
From the start of the design process, SIGMA took steps to minimize