>>3217524It's a variable aperture standard zoom with f/5.6 maximum aperture at 50mm and it extends three times longer when in operation. Pentax "WR" lenses do have a very high level of water resistance, but the more you move large plastic tubes in and out of each other like that, the quicker the weather seals are going to wear out.
I'm not a fan of Pentax's kit lenses, although I did take many great pictures with the previous (non-retractable) version of this lens, the 18-55 f/3.5-5.6. It was reasonably sharp in the center and the autofocus was quick and decisive (unlike so many Pentax lenses). The corners were always a little mushy, which is fine if you use it for snapshots while on trips, like I did, but the lens has enough flaws that I just wanted something better. It's a really useful lens, and lightweight, but I ended up selling it just to force myself to stop ruining so many photos with soft corners and color fringing. The reviews on the retractable version don't indicate that the optical design has been significantly updated. I would go with a different lens.
>and the variable aperture being at full-stops satisfies my obsessionsSome things in life are subjective preferences. This one is objectively dumb. There are lots of better options than this lens.