That is my question. Should I buy a F4 or an F5. As I am getting back into film in a big way I am looking at them. I really am only looking at the F4 because they were coming out when I was in school and I lusted for one of them. From a pracitcal side I think the F5 is the better choice. Are there any lens compatibility issues between them. I was looking at another site, and it mentioned modified F5s not straight out of the box F5s.