Lenses

Build quality
Optical quality
Value for money
Overall

Cons: CA huge heavy weight

Pros: weather resistant good AF motor quickshift

Summary: A bit expensive for what you get, however there is no weather resistant alternative. I would wish a little bit better performance especially if you compare it to the much cheaper tamron 17-50. However I would buy it again ;)

Build quality
Optical quality
Value for money
Overall

Cons: - too expensive at the moment - terrible QC (which apparently has been solved) - my 3rd lens with acceptable sharpness wide open - vignetting - chromatic abberation - no "smart" lens hood like Canikon 24-70mm f2.8 or Nikon 17-55mm f2.8 - best body K-5 only offers effecive image stabilisation of around 1-2 stops; only around 1 stop on K-r - AF speed slower than competition - 17-70mm f4 currently a better option as standard zoom for prosumers - relatively heavy - a bit bulky

Pros: - weather sealing - quiet - sufficiently fast focusing - smooth zoom and focus rings - lens hood offers door for adjusting polarising filters

Summary: This lens used to cost €590 in early 2009 and is now at around €800 which is pretty ridiculous. If Pentax / Ricoh would update the lens to match the Canikon 17-55mm f2.8 image quality wide open (and maybe the focusing speed and accuracy), then this would be THE lens simply because of the added weather resistance ans SWM.

Build quality
Optical quality
Value for money
Overall

Cons: - CA at the wide end (easily correctable in Lightroom and DXO). - It's a big lens and requires the battery grip to balance well on my K-5.

Pros: - Very sharp lens from f/4 onwards - Weather sealing - Silent focusing - At present (Jan 2011), the only 24-70mm f/2.8 (FF Equivalent) setup that is both stabilized and sealed.

Summary: I bought this lens in 2010, intending to use it at weddings. This lens has not disappointed and has performed admirably in all the weddings I've shot. The focal range is such that it covers about 70% of all the shots I take and it's easily my most frequently used lens. This lens is definitely worth a look, and it's a good investment.

Build quality
Optical quality
Value for money
Overall

Cons: distortions at 16mm, plastic/metal-mix lens tube

Pros: f 2,8 for low light, very good build quality, a lens for the most situations, good sharpness, good brilliance

Summary: maybe a lens for 70% of all photo motifs, one of the Pentax "allround must have lenses"

Build quality
Optical quality
Value for money
Overall

Cons: edge soft at 16-17mm lateral CA's at wide angles

Pros: versatile focal range excellent contrast/color fairly solid construction HSM/quick focus sharp beyond 18mm

Summary: A welcomed new series of motor driven lenses. Fast, responsive snd affordable.