Originally posted by Ed Hurst If you want a single lens to walk around with, it's hard to select a single prime unless your shooting style can guide that. It would be impossible for me to choose between the 55 and 75 alone, as I use both plenty. Some people would use one more than the other. If you want a single lens, I too would suggest the 45-85 zoom; it is not optically perfect, but certainly good from 45-65 and acceptable from 65-85. If you can tell us more about what/how you shoot, it might be possible to choose between the two primes.
I get around this quandary by almost always carrying around three lenses! But I am an obsessive idiot.
Ed, I wouldn't call you an obsessive idiot over lugging three primes and a 645z. An obsessive idiot would be one who back in film days carried a 645n, three primes including a Pentax 105 with 67/645 adapter, a Toyoview 4x5, 10 film holders, film for both formats and attendant camping gear/supplies for five days in a 75 pound backpack. I don't do that any longer. :-)