Nathan Gardner , Sep 09, 2012; 10:32 a.m.
I'm always curious as to why people are so concerned with shutter sound. I don't have a mk II to compare it with, but the 5D III doesn't sound extremely loud to me. It is a full frame mirror however, so it may be louder than an APS-C shutter such as the 60D or 7D. If you are concerned with the noise level, the 5D3 has a silent mode that works beautifully, allowing for faster successive shots than previous models (the 1D IV is my only comparison) and is even quiter. It barely makes a sound at all. I've used it in churches during weddings and I doubt anyone heard it.