Sigma has just recently (considering lens generally have 10 year product-life cycle) announced its brand new 35mm 1.4 prime lens. It has received rave reviews, and I think it’s an exceptional value, given it’s price-to-performance ratio.
Sigma has really stepped up its game within the past year or so. They’ve always offered compelling lenses at good prices, but the rub used to always be to “make sure you get a good copy.” What that means is that there was a variation in performance (specifically focusing) from lens to lens (so one 35mm 1.4 might perform better than the next 35mm 1.4 off the assembly line).
Well, Sigma has really stepped up their quality control as they developed a new proprietary lens testing mechanism, the A1 MTM. You can read about it here, but the bottom line is that QC is taken to the individual level. Nice!
Every new lens designed in the Contemporary, Art, and Sports lines will be tested with the A1 device–meaning 100% of the lenses built will be analyzed and approved before leaving the factory in Aizu. -Sigma blog
That said, to read more, see samples, and watch a video about the new 35mm 1.4 from Sigma, head on over here.