I am on the verge of purchasing a medium format Hasselblad camera. However, there are a lot of different types. Can somebody shortly explain to me the differences between the following models: <p> 500C, 500CM, 501C, 501CM, 503CX, ELM, ELX <p> What is the best choice if I use the camera for landscaping and portrait photography. <p> Thanks in advance. <p> Johan Ditzel.