Sigma 105mm f1.4 DG HSM Art
THE 105MM F1.4 Art combines the versatile 105mm short telephoto focal length with a superfast maximum aperture of f1.4, making it the ideal lens for applications such as portraiture and astrophotography. The inherently shallow depth-of-field at f1.4 allows for the creative use of selective focusing, with a smooth and linear transition from the in-focus areas to the out-of-focus areas. The optical design optimises sharpness, contrast and brightness across the image frame, while also minimising distortion and aberrations.
The external construction employs metal barrel tubes with full sealing against the intrusion of dust or moisture, and a rubber gasket around the lens mount. The mount itself is machined from solid brass to ensure long-term precision and durability. Additionally, the exposed surface of the front element has a special coating to help better repel water and grease. The lens hood is made from CFRP (carbonfibre re-enforced plastic) to reduce weight without compromising strength, and the detachable tripod-mounting collar has an Arca-Swiss type plate which is compatible with a wide selection of platforms and clamps.
The optical construction comprises 17 elements in 12 groups and six of these are special types, including three made from FLD
(‘F’ Low Dispersion) optical glass and two made from SLD (Special Low Dispersion) glass to minimise axial chromatic aberrations. The
FLD elements have been formulated to give similar anomalous dispersion characteristics as fluorite types. Sigma’s ‘Super Multi-Layer Coating’ reduces flare and ghosting, further enhancing sharpness. A more rounded, nineblade diaphragm delivers smoother-looking out-of-focus effects.
The ‘HSM’ ultrasonic autofocus drive gives fast, smooth operation and allows for a full-time manual override. The minimum focusing distance is 1.0 metre, giving a maximum reproduction ratio of 1:8.3. The 105mm f1.4 Art lens is compatible with Sigma’s USB Dock which enables firmware upgrades and adjustment of various parameters via the Sigma Optimisation Pro software. The choice of mounts is for Nikon, Canon, L-Mount, Sigma SA and Sony.