Originally posted by cport I am interested in your feedback about SDM behavior of Pentax DA* 55/1,4.
While the lens may be useable at the moment, I guess the decision you must consider is "If the SDM fails, are you prepared to use it as a manual focus lens for the rest of its life? Will you be happy having paid AF price for a MF lens?"
If so, you can keep the lens. If not you need to gamble that the SDM will not fail.
I haven't factored in the cost of repairing the lens, which is another issue, and would be worth investigating.
disclaimer; I have no SDM lenses, so no skin in the game.