Back focus button When you press the button to take a photo, it’s actually a two step process : just as you press the button ( or if you press the button lightly), the lens automatically focuses on your subject and then takes the photo - it feels like it is one action, you press the shutter button (the button to take the photo) and it takes the photo. But did you know on most cameras you can separate the focus and the release (taking the photo) Some cameras have the ‘back focus’ button which is