I have been shooting with my trusty Canon 5D mk2 for almost four years now. I got it as soon as it came out. It has been a great camera and between it and my backup has shot well over 100 weddings as well as a trip to Kruger National park and several assignment shoots, including a trip to the Virgin Islands for Sail Magazine. (That was a rough week on a yacht). I was very happy with my mk2 except for one thing. The auto focus was slow. It was great for portrait work, but once the light got low or any action started I was stuck with centre point focus only and it was hit and miss. Wide apertures like 2.8 or certainly 1.4 on my prime lenses was out of the question in low light. My old Canon 20D had the same auto focus and that was a 2005 model.
After trying a Nikon D3s with a 70-200VR at a few weddings, I was sold on either switching to Nikon and getting a D4 or used D3s, or getting a 5D mk3 and hoping the hype about the auto focus was true. After getting my mk3 three weeks ago and shooting four weddings with it and three engagement shoots, I am sold on it. I am glad I did not jump ship. I far prefer the skin tones on Canon, but apart from that I find Nikon and Canon are really both exceptional systems.
I cannot believe the speed of the 5D mk3 auto focus and the accuracy. I have been shooting brides getting ready at f1.4 and nailing the shots, dancing and action even at f1.8 are crisp and even using the outer edge focus points. I have my focus set to manual selection of only the cross type points most of the time with expansion on and off depending on the light. So far that has been amazing.
All the talk of only one mega pixel more and only one stop of low light performance takes away from the huge advantage of amazing autofocus and I am glad I upgraded. Some may ask why I did not consider the Nikon D800. It was not a realistic option for me as a wedding shooter. I already come home with 35 gigs of raw photos and the D800 is just far too many pixels for weddings in my mind. I have a good friend who had one and returned it after three weddings and went back to a D3s. I found the images no better than my 5Dmk3 in normal light and in low light above ISO 2000 the Canon destroyed the Nikon D800. Since I often shoot up to ISO 5000 when churches do not allow flash the Nikon D4 or a Canon 5Dmk3 or 1DX were my best options. If i was a landscape or studio photographer a D800 would be a great choice in my mind, if I did not own several Canon lenses.
Anyway, this is getting long. Thats just my five cents on the first three weeks with the Mk3. Happy with my upgrade and looking forward to getting a second one soon. Till then my trusty 5D mk2 is a great second camera. Here are a few quick edits of some recent Mk3 shots. Enjoy.