I am new to medium format and very interested in 500 serise. i want a 500 camera that can last me fairly long time so it can adapt digital back and other possible new feature. for those reasons i am set between 503CW and 555ELD. But i do not know which one to get, and the reason getting one over another. Can you guys give me an advice? or you guys think 500 serise is not a good camera to start with, which you will recommand, to some one how use friendly with AF and MF 35mm SLR, mainly portrait, people, sometimes landscap. thank you for help me out.