Sigma 85mm F1.4 DG
the Sigma 85mm F1.4 DG DN | Art. This short telephoto prime is the first with a fast f/1.4 aperture that the firm has designed specifically for mirrorless cameras, starting a new line that will complement its existing set of f/2.8 zooms. It’s said to be ideal for portrait, wedding and event photographers.
Sigma 85mm F1.4 DG DN Art, with hood, on a Sony A7-series body
Sigma claims that the new lens delivers improved image quality compared to its counterpart for full-frame DSLRs, yet weighs only slightly more than half as much. Optically, it comprises 15 elements in 11 groups, including five super-low dispersion (SLD) elements and an aspherical element to combat optical aberrations. Particular attention has been paid to eliminate colour fringing around out-of-focus elements, a symptom of axial chromatic aberration. It also employs a diaphragm with 11 curved blades to give a circular aperture for attractive bokeh.
The lens features a de-clickable and lockable aperture ring and an AFL button
Along with excellent optical performance, the firm is promising high-speed AF and robust build, with dust- and splash-proof construction. It’s employed a stepping motor that’s designed to work well with both phase-detection and contrast-detection autofocus. The barrel features an aperture ring that can be de-clicked or locked, along with a focus-mode switch and an AF-lock button whose function can be customised from the camera body. The supplied bowl-shaped lens hood has a locking button for additional security.