Sigma is undoubtedly disrupting the market. Although we can’t really comment on the handling, AF operation, or build, the optical quality is equal, and in some cases superior, to the big brand names. That in itself wouldn’t be so disruptive if there weren’t such a price disparity. The fact that the Sigma 24mm f1.4 is available at around or more than half the price of the Nikon and Zeiss models and can compete with the more affordable options makes it all the more attractive. At just $849 currently, it is a thoroughly compelling choice, and particularly so if looking for an AF model.