I'm using Hoya HD UV filters for my 16-50mm and 60-250mm, HD series belong to the top line of Hoya. They are made of specially strong glass and the optical quality is good as well. Alternatively, you can choose UV filters from B+W, some people say they are the best. I use the B+W MRC UV filter for my Nokton 58mm.

Mine is completely fine, and I bought it from SRS couple of weeks ago.

I change the lenses whenever it's necessary. But most of the time, I change between 16-50mm and 60-250mm. I only use the Nokton 58mm for special situations, for example, low light or I want strong bokeh.

I don't blow the sensor every time I use it, but on a regular basis, like once per week.

Bought the Pentax K20D + 16-50mm + 50-135mm bundle from SRS couple of weeks ago, arrived the next day. I also bought a 50mm f/1.4 and a camera bag afterwards. More recently I exchanged my 50-135mm with the 60-250mm.

So I did buy quite a lot of stuff from SRS. I would say they've been always helpful, excellent service and communication. Unfortunately, I hadn't joined this forum yet when I was ordering, so I didn't get the free postage treatment. I've placed SRS as my favorite camera dealer based on their price and service.

From what I know, this one was discontinued. But Pentax will release smc Pentax-DA 1.4X Rear Converter SDM* teleconverter soon.

Here are some more pictures.

Just received mine this afternoon, I noticed this issue as well. I guess we should call it 60-235mm rather than 60-250mm.

As I know, 16-50 is less sharper than 50-135 in general. From what I see, the pictures are pretty sharp.

Mine too , can't wait to go and try it out.