Originally posted by twitch It's a small step up in image quality, but a big step up in range (135mm vs 55mm).
The DA 35mm 2.4 AL is a very big step up in image quality vs any of the Pentax zooms (including the much more expensive 16-50 SDM lens).
I agree wholeheartedly with both statements. I own all three lenses - the 18-55, the 35/2.4, and the 18-135. The 18-55 sees little use anymore because the 18-135 is faster focusing. slightly better image quality, and has a better reach. Also, it is silent in operation which disturbs those being photographed less for better candids, etc. The 35/2.4 is truly an outstanding performer IMHO, it gets a few bad comments because it doesn't have an aperture ring (don't need one with dSLRs), has a plastic mount (none have been reported to have failed on Pentax cameras), and does not come with a hood (they're $3 on ebay). It's image quality though is truly solid and as Twitch said, and he ought to know, is better than the zooms - even the high priced ones like the 16-50.