Sigma shows new glass, lenses

Sigma Corp., Japan, is using FLD (“F” Low Dispersion) glass, with performance equal to fluorite glass, in its new high performance lenses. Sigma says FLD glass is the highest level low dispersion glass available with extremely high light transmission. This optical glass has a performance equal to fluorite glass which has a low refractive index and low dispersion compared to current optical glass. It also benefits from high anomalous dispersion. This, says Sigma, gives excellent correction for residual chromatic aberration (secondary spectrum) which cannot be corrected by ordinary optical glass and ensures high definition and high contrast images.

FLD glass offers superior optical performance, equal to fluorite, at an affordable price, the company notes. The density of FLD glass is lower than traditional optical glass, ensuring a lighter construction of large aperture lenses.

FLD glass has been incorporated into some of its recently announced lenses; four elements in the 8-16mm f/4.5-5.6 DC HSM as well as two elements in both the APO 70-200mm f/2.8 EX DG OS HSM and the 17-50mm f/2.8 EX DC OS HSM.

Sigma 8-16mm

The new Sigma 8-16mm (12-24mm equivalent) is the first ultra-wide zoom lens with a minimum focal length of 8mm, designed specifically for APS-C size image sensors. This lens has an equivalent angle of view of a 12-24mm lens when used on digital cameras with an APS-C size image sensor. As well as the four FLD elements, there’s one hybrid aspherical lens and two glass mold elements, giving excellent correction for distortion and astigmatism, says the company. Super Multi-Layer Coating reduces flare and ghosting while superior peripheral brightness ensures high contrast images throughout the entire zoom range. This lens incorporates a Hyper Sonic Motor, ensuring quiet and high speed AF as well as full-time manual focus capability. It has a minimum focusing distance of 24cm throughout the entire zoom range. This lens has a length of 105.7mm and a maximum diameter of 75mm.

The new Sigma 17-50mm is a compact lens with an overall length of 91.8mm (3.6 inches). With Sony and Pentax mounts, the built-in OS function of this lens can be used even if the camera body is equipped with an image sensor shift anti-shake system. There are two FLD glass elements, plus two glass mold lenses and one hybrid aspherical lens, providing excellent correction for all type of aberrations. Super Multi-Layer Coating reduces flare and ghost. This lens has superior peripheral brightness and provides sharp, high contrast images even at the maximum apertures, says Sigma. High image quality is assured throughout the entire zoom range. It incorporates a Hyper Sonic Motor.

The APO 50-500mm incorporates Sigma’s original Optical Stabilizer function. With Sony and Pentax mounts, the same situation as noted above applies. Four SLD (Special Low Dispersion) glass elements provide excellent correction of color aberration, while Super Multi-Layer Coating reduces flare and ghosting. The lens also incorporates a Hyper Sonic Motor, ensuring quiet and high speed AF as well as full-time manual focus capability.

Sigma 70-200

Sigma’s APO 70-200mm lens incorporates the company’s original Optical Stabilizer function. For Sony and Pentax mounts, see the note above. Two FLD glass elements and three SLD (Special Low Dispersion) glass elements provide excellent correction of color aberration. Super Multi-Layer Coating reduces flare and ghost. This lens uses a Hyper Sonic Motor.

The Sigma 85mm f/1.4 EX DG HSM, when used on digital cameras with an APS-C size image sensor, effectively becomes a 127.5mm lens. One SLD glass element and one glass mold element give excellent correction for all types of aberrations and ensure superior optical performance. This lens is equipped with a rear focus system that minimizes fluctuation of aberration caused by focusing. The Super Multi-Layer Coating reduces flare and ghost even in backlight photography. The lens has a Hyper Sonic Motor.