Originally posted by Buddha Jones Are you just saying that because every lens you have is a Sigma
Not in the slightest.
I own the 18-125 because I've had it since day 1 with DSLRs, it's sharp (I must have the only good copy of this lens on earth!) and is a perfect walkaround lens for me.
I own the 50-500 because there were no 80-200's available from Pentax and no 70-200's available from Sigma or Tamron.
I am very seriously considering buying a DA*50-135, depending if I get a contract to shoot a particular event. However my next lens will most likely be a Sigma 10-20. Pentax make the 12-24, but those extra few degrees AOV out of the Sigma will be handy for it's intended purpose.
To sum it all up, I buy the lens that fits the job I wish it to do.
Pentax doesn't make a f2.8 lens in this focal range so other options need to be explored. I find I use the 40-70mm range an aweful lot so this lens fits. The DA*'s don't. Tamron is hardly available where I live so that option is out for me. In addition I know, and have used, this lens in another mount and am very happy with the results, hence why it's on my shopping list.