Originally posted by pomabille Hi everyone,
I just wanted some input on an issue I started having recently.
After much pondering, I purchased the controversial da* 16-50 about 3 week ago, brand new.
In the first little while, I've put it through various tests and tricked the autofocus, and overall I was pretty happy with it. Yes, it's a quirky lens, but the learning curve seemed worth it.
Without warning, or any other changes whatsoever, something strange started happening. The lens stopped focusing, but only some times.
I have a success rate of about 20% when pressing the AF button (I'm a bbf'er). The lens will mostly try to focus and stop, in a random position, with the AF indicator blinking in the viewfinder, or a red indicator in live-view.
Addly, it seems that, on some instances, the focus ring doesn't catch the focus scale in MF. I have to rotate the ring the other way, and then in the way I originally intended once it caught it. This points me towards a mechanical problem.
C$1,300 later... This was the 2nd of 2 lenses the store had. The first one was an complete lemon and the girl sent in back to Pentax! Yikes!
Cleaned the heck out of the glass, of course, and tried all the AF modes, all with the same result. Latest firmware installed.
Any input will be much appreciated!
Thank you!
Could be the infamous SDM problem.
Mine did exactly that before failing altogether ... this lens is now "screw drive only" via a hack which can be found on this forum.
If that lens is fairly new, I would advise to send it back/bring it back to the seller for replacement (again?)
JP