Total newbie here! I have a Nikon D5500 - when I bought the camera I had no clue there was a difference between auto focus and manual focus so I have ALWAYS manually focused the camera. I want to start working with auto focus as it will be more reliable and more efficient. No matter what lens I have on my camera, when I press the shutter button half way down the camera does not focus. I have to continually manually turn the focal ring and look for the green dot in my viewfinder (which is never actually green just sort of blinks)... any advice on what I'm doing wrong?
In the manual p78 or so, there's a handful of conditions that the autofocus would have problems getting a fix. When I play around with a test shot with my Olympus, if I try to get a lock on a blank wall, it would usually fail.
Does the lens go in and out of focus when you try to get a fix?
An alternative could be that your settings have been reconfigured for back-button focus, and the half-press does not activate auto-focus. But that shouldn't cause a green blink...
Another thing you could double check is try to auto-focus in live view.