Originally posted by TheGrandPrixKid Hi I'm on my second Da* 300 (first one bought in July 2011, second may 2016) the first I sold end of 2015 due to slight focusing issue and feared it might be sdm failing. Now my new copy which is only 4 months old is no longer able to focus at all. All I get is micro adjustments back and fought then long way in slam and then all the way back and slam. My first one did this on occasions but this one started day one out of the box. Am I correct in thinking this is an sdm failure. Thanks for your help.
If this happens only with this lens, it may be the lens. However, your mention that it happened occasionally with your previous copy leads me to suspect it might be an issue with your focus sensor, which I believe is located in the bottom of the camera cavity. Before you go to all the trouble of sending the lens in for warranty repair, you might try giving the camera cavity (particularly the bottom of the cavity) a blast of air or two to see if the problem persists. Also, worth cleaning the contacts on your camera to make sure that is all good. My 2 cents...
Daryl
---------- Post added 09-17-16 at 08:35 PM ----------
Let me add that the typical SDM failure is characterized by no auto focus action by the lens at all. In the pre-sdm failure timeframe, the lens is sometimes slow to "wake up" but does eventually when aimed at a high contrast area and the focus button (or half press of shutter) repeatedly pressed. Bottom line, what you have described does not sound like a typical SDM failure.