I purchased the 50-135 from Amazon here in the U.S. aprox. 1.75 years ago. after about 1.5 years the sdm motor started getting sluggish and requiring more and more time at startup to respond at all. First about 5 seconds, and ultimately over a minute and then not working at all requiring manual focus. The out of warranty repair cost is 190US$ plus about $10 shipping each way. It is being repaired by Pentax' factory authorized repair company-- C.R.I.S. in Arizona. They said it may take up to 6 weeks but could be faster.