If you've wondered as I have, how a photo taken using the black and white setting on a camera compares to a colour picture that had been changed to black and white in iPhoto you've come to the right post. Can you guess which picture was taken in black and white and which one was originally in colour? All I did was change the "Optimize Image" setting from Normal to Black and White. Everything else remained the same.
I bet you guessed correctly. The first photo, which I feel looks much richer and has much nicer contrasts was taken in black and white mode. I think I'm going to try use it a little more often.