1) How do I open the back? I think it's an older back with only one button on the side. It sure doesn't seem to want to open. Hard to load film to test the body this way. 2) How do I mount the hood? Only way I can get it on is at an angle to what it should be. The normal hood for the 75mm. 3) The pro hood I got came with a 58mm attachment. Can I just pickup a 62mm attachment for it?