Although I didn't ask the original question: Thanks for this excellent explanation, with so many example calculations that it's impossible not to "get" it!


It clears up some things that I had been wondering about while considering whether to upgrade to a 7DmkII or a 5DmkIII (from my current 500D/T1i) ... and since it confirms my suspicions about crop factors, apertures, and iso-numbers, I'm starting to lean much more towards the 5DmkIII.


Regards, Colin