For a long time, I was making closeup photographs of flat surfaces using my cropped DLSR and Canon EF 50/1.4 lens. The scene was illuminated by an external flash. The focusing distance was the closest ...
Reading this answer I realized that I didn't know the difference between the two depths (of field and focus). Browsing related questions didn't reduce the blur (!) between the two... Wikipedia ...
What is back-focusing? Is it something I need to be worried about, or can I just live with it? How can I tell if my camera/lens is sufferring from it?