I recently bought an NEX-6, the 24mm F1.8 (SEL24F18Z) lens, and the black 18-200mm F3.5-6.3 (SEL18200LE) lens. I love the 24mm lens, but I'm having a what I believe one would call a "focus hunting" problem with the SEL18200LE. Basically, if it's in AF-C mode, it nearly always focus hunts. The severity of what I would call a "pulsating" image in the viewfinder depends on the aperture and focal length, but varies from slight to quite pronounced, far beyond the point of distraction. It doesn't matter whether the camera is handheld or on a stable surface, whether I'm using it inside or outside, or whether it's pointed at a distinct small object or at a large surface like a wall -- it does it in all those conditions.
I've updated my NEX-6's firmware to version 1.01, and the camera reports the 18-200mm lens as being at version 02, which as far as I know is current.
I've called Sony technical support about this. They didn't have an SEL18200LE immediately available to try, only the (silver) SEL18200, and said they were seeing the same thing with it, so their immediate response was that it's "normal behavior" -- that the camera is "anticipating scene changes" (their words).
Am I correct in my assumption that focus hunting, with a distractingly pulsating viewfinder, is most definitely not "normal behavior", whether for cameras in general, for the NEX-6, or for the SEL18200LE specifically, and that I shouldn't be satisfied with this?