If you haven't yet, try and find the macro mode or setting or what have you on your camera. It's frequently depicted with a flower icon. That should convince the camera to focus closer for you (assuming it has such a mode to begin with. YMMV).
Printable View
Second, place the blade in front of something that is DIRECTLY behind it, like a book or something so that the auto-focus isn't having problems in finding the right depth.