No camera (that I know of) will reliably focus at 1:1, heck 1:2 or 1:4. It is best to manually focus. It takes practice but the best way to do this is manually set the focal distance on the lens. When starting out set the magnification to say 1:4. then practice photographing a static subject - like a flower. Be sure auto focus is off. Then physically move your body forward until the subject comes into focus and fire the shot. If you push to far into the focal plane, gently rock back and then rock forward towards the subject and try the shot again. The key is getting the timing of pressing the shutter when the subject comes into focus. When pressing the shutter button, gently depress it, don't mash it as it will throw your framing off. This method takes practice but is very effective in teaching you how to manually nail the focal plane you want.
