06-25-2014, 06:34 PM
I also had some troubles with the Tamron 17-50 on Pentax and the lens travelled more than me by sending it from Switzerland to Tamron Germany. Twice, once with the body. At that time I wasn't used to the shipping costs 
Thanks for reminding me, dave's clichés how much easier my life is since i abandoned the Pentax boat. On the other side, at the time I had some Pentax and Sigma lenses I had not idea what happens if a lens is decenterred. And am pretty sure, I wouldn't have been able to recognize one. Anyway, I was pretty happy with my 4 Sigmas at that time.
Talking of moving elements of lenses: I always remained sceptical to Pentax' inbuilt vibration reduction - a moving sensor brings another variable into the game. What, if the motors or electronics is a bit faulty? Trying to compensate shutter vibration can fail.
Thanks for reminding me, dave's clichés how much easier my life is since i abandoned the Pentax boat. On the other side, at the time I had some Pentax and Sigma lenses I had not idea what happens if a lens is decenterred. And am pretty sure, I wouldn't have been able to recognize one. Anyway, I was pretty happy with my 4 Sigmas at that time.
Talking of moving elements of lenses: I always remained sceptical to Pentax' inbuilt vibration reduction - a moving sensor brings another variable into the game. What, if the motors or electronics is a bit faulty? Trying to compensate shutter vibration can fail.