Pentax smc DA* 16-50mm f/2.8 ED AL (IF) SDM

I have had this lens for more than a year now and my experience is unfortunately quite mixed. I used it mainly for landscapes, with additonal filtering (Hoya Pro 1 D polarizer and Cokin P system).
At the very beginning I noticed the front element was a bit loose (could move about 1mm front and back without zooming), but was ensured this was not a problem. Later on (after about 6 months) it suddendly stopped to focus - or at least I thought so. Actually, the SDM was still operating, but unbelievably slow.... and I mean it! It took about 40-50sec to refocus from close distance to infinity. Then (about a month ago) the zooming got stuck and could not be moved. The lens is now of zero value to me. Repair would cost about the same as new lens..... So mechanically - very bad lens (just my experience though).
Optically it is not satisfying my needs either. The angle of view is great and distortions fine. Also sharpness and color accuracy is OK for a zoom lens(although quite far from my other lenses - Pentax 40mm and 70mm Limited). But for its main purpose, wide-angle landscape shots, it did not prove to be a good choice. It has very visible chromatic abberation, mainly on trees against sky. It also shows quite a lot of flare. I was also unable to achieve shots without vignetting on the 16mm end, when using polarizer and graduated filter.
Although I was expecting quite a lot from this lens, I am not using it anymore. What a shame Pentax.....

- Weather sealed
- Sharpness
- Color accuracy

- Questionable durability/solidness (definitely in my case)
- Poor flare resistance
- High level of chromatic aberration
- Needs the largest (and most expensive) square filters (vignetting is visible even with a wide-angle adapter for Cokin P system)
- High price

None

OK