I finally bought a lens which I've been looking at for years. Since I'm not a victim of LBA I buy lenses rarely and cheaply. This time it was Tamron AF 18-200 mm Super Zoom.
Why buy a low cost obsolete lens that the experts would never consider?
Cost - I bought it from B&H for $289 with free shipping.
Old Model - Since Tamron and Pentax started selling the 18-250 the cost of the earlier model plunged.
Sell my KIT lenses - Get a little of my investment back. I have two sets now so can part with one set.
Versatile - I no longer need to carry both "KIT" lenses to cover 18-200.
Clean Sensor - This is the real big reason. I've been plagued with dust on the sensor of my K100D from day one. I do all the proper things: change lenses in low dust locations, change lenses quickly, aim the camera slightly down to keep dust from falling in, etc. I use my Giotto Rocket Blower regularly.
A few months ago I had to resort to wet cleaning, several spots would not come off with the blower. Last week I got some more blower resistant spots.
So I'm going to do something an SLR lover would call heresy - I'm going to dedicate my K100D to one lens. It has enough range to do whatever I need on a day-to-day basis. My K110D is a dedicated Astro camera. I can do this now because I recently came into an istD that will be my Macro camera. Having a camera per lens may seem extravagant but consider what these older models are worth these days. I still have a second K100D which has not had a lens assigned yet. It may get the Pentax 75-300 for bird photos. Four years ago I was a dedicated K1000 user, avid lens changer, and never heard of a DSLR. Now I have four DSLRs.
Today I took about 80 shots with the new Tamron and I like it. I was at the Dog Park where you need to quickly switch from close up to telephoto as the dogs run all over the place. I used to be stuck with the 18-55 since there was no time to switch lenses for the long shots.
I'm not that critical or artistic to tell the quality difference between the 18-200 and the two KIT lenses. I did take an f22 shot of the sky and found I had MANY spots. I did my second ever wet cleaning and though not perfect, it is WAY better. The most offensive spots vanished, 80% of the less offensive ones are gone, that which remain can easily be fixed with Post Processing. Now the new lens is on for the foreseeable future!