Auto Focus dead on SMC DA 55mm :0(

Started May 14, 2017 | Questions thread
andrew britten Senior Member • Posts: 1,182
Re: Auto Focus dead on SMC DA 55mm :0(

Ken, please try these methods that have worked for me, as described. The last method is the most successful, so far. No guarantees, of course.


"I have the same problem with the 16-50. It needs kick-starting after a few days sitting idle. What works for me is using Live View to get it going again. It still needs a little encouragement by pre-focussing manually, while activating AF, and getting the confirmation beep. Then I aim a little further or closer - just either side of focus - and let the AF do its thing. This can take 3 - 4 or more attempts, but eventually it will start working - for me at least. Then I let it rack backwards and forwards a few times, and it behaves for the rest of the day.

My 'theory' is that for some reason there's more power available to the SDM in Live View, but I really don't know that. I do know that I have little luck using normal PDAF through the viewfinder to get it going, but it does operate normally (in viewfinder AF) after I've kick started it in LV.

The method also works a treat with the DA* 50-135 2.8, a lens I had repaired (at great expense and time) a few years ago. Unfortunately it failed again not long after that. From there I decided to repair it myself using the internet method, and that's been working for around 4-5 years now.

Maybe more, as I just realised it's in its 10th year!


Further to this I've found I can quite easily unstick my lenses with a wired remote, and the camera in Live View. No jiggling of the focus ring necessary.

This is on a K3 and with the 16-50 SDM and 50-135 SDM lenses.

Hope this may work for others.


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