Andy Westlake investigates the latest addition to Sigma’s ‘Art’ line of high-quality fast primes
Sigma 24mm f/1.4 DG HSM | A review – Features
With an optical formula of 15 elements in 11 groups, Sigma has chosen a relatively complex design for this class of lens (Canon and Nikon’s equivalents use 13 and 12 elements respectively). Sigma hasn’t skimped on the special glass either, with three ‘F’ low-dispersion (FLD) and four special low-dispersion (SLD) elements used to minimise chromatic aberration. Two aspherical elements are also employed to reduce distortion and coma flare.
Autofocus employs an ultrasonic-type Hyper Sonic Motor, with full-time manual override on offer. A switch on the side of the lens engages manual focus, which can be aided by a small distance and depth-of-field scale on the top of the barrel. As with most modern AF lenses, though, the markings are too closely spaced to be widely useful. The minimum focus distance is 0.25m, giving 0.19x magnification.
A nine-bladed aperture diaphragm provides settings from f/1.4 to f/16, and manages to maintain an impressively circular shape throughout the full range. This should help give an attractive rendition to out-of-focus backgrounds. The lens is threaded for 77mm filters, and has a bayonet mount for the supplied petal-shaped hood.
Initially, the lens will come in versions to fit Canon, Nikon and Sigma DSLRs, in line with Sigma’s recent practice. We wouldn’t be surprised to see a Sony Alpha-fit model turn up sooner rather than later, and with Ricoh’s announcement of an upcoming full-frame Pentax DSLR, we can but hope that Sigma will eventually make a K-mount version too.