I use Olympus E-510 and E-520 bodies with various lens and am thinking about an extension tube for use with my 50mm macro lens. Now my problem. My vision is deminished and focus is difficult for me. I use auto focus almost exclusively because of this problem. The Olympus site says "manual focus recommended" for the extension tube. Has anybody here had experiance with this set up that can tell me how effective or in-effective the auto focus is with the macro lens? Any help will be greatly appreciated.