my equipment is in good condition, no calibration required. it's a point of your own demands. 24/70 is the best allround lens in it's class. but if there's a question of portability and someone asks for sigma or tamron I would prefer the older nikon primes over third party. if there's a question of quality I'd prefer the newer nikon primes over 24/70. if someone asks me for best sharpness, contrast, color depth I'd prefer mf with primes over ff. zooms are for hectic or reportage situations like sports, weddings, children, etc.. but why no zooms for leica m9, no zooms for leica s2 and I haven't seen anybody using a zoom on hassy or mamiya? in summary I'm not satisfied with the output of 24/70 in those situations I need it to use but it's better than anything else then. that's what I call compromise lens.