Originally posted by reeftool I have a DA 40 Limited that has sticking aperture blades in cold weather. I have pretty much the same results, overexposed shots. Bringing it back inside cures it for now but it's going in for repair soon. Your lens is probably behaving similar. Are you shooting on a camera with live view? Engage the DOF preview and that will tell you right off whether the lens is stopping down or not.
i did not use liveview but i did use the optical dof preview and i noticed that it take a while stopping down.
anyway, tomorrow i will order a new one