Originally posted by bdery The green are being replaced by the newer reds. The three differences (apart from the colour) are :
1-all new lenses (except, I believe, the 40) have rounded aperture blades (good for bokeh, bad for starburst effect).
2-All new lenses have the newer HD coating. The previous coating was already fantastic, this one should be better, though from my personal tests with the 21 it's quite hard to see any difference.
3-The newer lenses ditched the "Pentax" lettering, replacing it by a more business-like focal length/aperture engraving. I don't like it
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Great post! I was going to make most of the same points. I would add that from my perspective the new versions represent a SLIGHT net improvement. While the old lenses have superb resistance against flare any improvement in this regard is a plus. On the other hand I love the star bursts that the "green ring" lenses provide. Moreover, in my experience rounder aperture blades do very little to improve bokeh. I also prefer the looks of the green ring versions. So on balance I would pay up to $50 more for the improved coatings, but at any price premium above that I would grab the green-ring versions. IMHO.
I would also note that there is no comparable lineup from Nikon, Canon, or Sony. The combination of small size, excellent "real world" performance and superb aesthetics makes these lenses a pleasure to use.
Dan