Conclusion: When Sigma first announced the 50mm F1.4 EX DG HSM in March, our story headline (courtesy of our news editor and punmeister-in-chief) was 'A new standard?', and this has turned out to be remarkably prescient. This new lens essentially redefines its class, and for once the results really live up to the marketing hype; compared to previous designs, we see significantly improved sharpness at large apertures (presumably due to a reduction in aberrations through the use of an...
Pros: Class-leading image quality, Relatively low vignetting even at wide apertures on full frame, Reasonably fast and positive autofocus, with full-time manual override, Very good build quality
Summary: The Sigma 50mm F1.4 DG HSM | Art is distinctly large, heavy and expensive for its type. However this is more than made up for by its fast silent autofocus, solid build quality, and absolutely outstanding optics. Overall it stakes a very serious claim to be the best autofocus 50mm prime on the market right now.
Pros: Stunning image quality - super sharp, minimal CA and practically no distortion, Impressive flare resistance, Generally attractive rendition of out-of-focus backgrounds, Fast, silent, and accurate autofocus, Excellent build quality
Cons: Large and heavy for a 50mm F1.4 prime, Relatively expensive for its class, No weather sealing
Excerpt: Similar in size, features, and price (though not format) to Sigma's 30mm f/1.4 high-speed "normal" prime for DSLRs with APS-C sensors, this 50mm full-framer ($500, street) also belongs to Sigma's EX family of pro-quality glass. Unusually expensive compared with 50mm f/1.4 glass from Canon, Nikon, Pentax, and Sony (the Pentax streets for $200), the Sigma scales up to an 80mm on most DSLRs, and is available in all popular mounts except Four Thirds.
Excerpt: It is hard not to be drawn to a fast prime - the short, fat, solid-feeling lens with very low-light capability is very attractive. So, I don't find it surprising that the Sigma 50mm f/1.4 EX DG HSM Lens has received a lot of attention in the early days of its availability.
Summary: Sigma are clearly marketing this optic as a premium alternative to manufacturer's own lenses. In some respects the higher price is justified, but in others it is not. How you use the lens as well as the camera system you use will be the biggest factors in determining whether this lens is good value to you.
Pros: Excellent sharpness in the centre at most apertures, Low vignetting, 77mm filter size is the same as most professional level zooms
Cons: Maybe a little softer than I'd hoped at f/1.4, Heavier than any other 50mm f1.4 lens, Bigger than any other 50mm f/1.4 lens
Excerpt: The ever-alert Sigma has read the signs well. It has offered a selection of f1.8 speed prime wide-angles – 20mm, 24mm and 28mm – for a while and, more recently, introduced a 30mm f1.4 designed for “APS-C” format D-SLRs (which effectively becomes a 45mm f1.4). The new 50mm f1.4 is another DG-series lens; Sigma’s designation for its 35mm format models suitable for either film or digital SLRs.
Excerpt: Combined with a fast aperture of f1.4, it represents a lens that’s a lot more versatile than anybody born and bred on zooms probably realises. However, the performance challenges remain the same as they did in the 35mm era except that they’re now somewhat greater when it comes to digital capture onto imaging sensors.