Originally posted by landofcourtness 
I'm not sure what you guys are saying here? Are you that by setting up Back-Button focus, that it could be the reason that it appears to be happening less? In terms of Back-Button focus, I don't quite use it the way most would think when considered when they say Back-Button Focus. I guess I do the opposite, where pressing the AF-button stops the AF when pressing the shutter (if that makes sense)
It could be depending on your setting. If you enable Back Button focus you have the option to disable the shutter button half press (ENABLE AF2). If you choose that option then you perhaps wont see the green indicator light up. I don't have my camera handy to test.
You have set up the BBF to the third option (CANCEL AF) Maybe that turns off the green light.
Perhaps you can do some testing and give a definitive answer ?
Of course it could be that your AF module is out of alignment. How well does your camera autofocus ? As Steve said the PDAF and the green light are part of the same system.
Similar Threads 
