I am looking to upgrade my old 5d to a new MKII or 6d.
I was set on getting the 6d but then I began to browse through hundreds of photos on flickr and the like to get an idea of the general 'look' of the respective camera's output.
I noticed that although the 6d looks more natural on landscapes and it far outperforms on low-light, the images of people seem a bit soft and gray in comparison to MKII images.
mind you I chose my 5d first series because I thought that portaits looked a little more authoritative, for lack of a better word.
today I checked-out a 6d and a MKII in a shop and got a feel for the cameras but it really is impossible to know how they are going to behave unless you are shooting a model etc.
so my question is aimed to those who have used MKII's extensively and have used 6d's as well in real-world portrait photography.
I have complete faith in the 6d's capacities in landscape, low-light etc. but my primary interests have more to do with how skin tones come-out as well as how much weight the profile of the person has in relation to the background etc.
anyone see an artistic advantage with the 5dII's IQ?
I personally liked the 5D Mk III's colors over the 6D. You are right that the 6D has more neutral colors, yes you can edit colors to be anything you want, but if you look at comparisons the 5D Mark III actually has a better color depth in back to back tests, so you end up losing some color information that you can never get back with the 6D, at the cost of having more neutral tones.
So in the end the 5D Mark III has some more noticeably tainted colors, (in a good way if you ask me), but the color information is also noticeably higher quality.
I would also strongly disagree with those who say that the 6D is better than the 5D III in low light. This is an optical illusion. The 6D has less color noise but more grain. Meaning that they actually will have identical levels of noise, as shown by tests, they just require different noise reduction settings. The 5D Mark III is just uglier unprocessed.
Also the 6D at iso 102400 is actually iso 70000 while the 5D Mark III is iso 77000, and there are other discrepancies between the ISO ratings. In the end again both have identical levels of noise over the whole of the frame.
The 6D does have a better center AF point, enabling it to work in ultra low light, but it's autofocus is very poor and outdated, and essentially a 5D Mark II autofocus system with some added spice. The 5D 3's autofocus is much better.
The 6D has much better dynamic range though, and I would love it if the 5D III had that dynamic range, and the ultra sensitive AF points for certain rare situations where I find myself needing those, bu the 5D III offers more features that are more broadly beneficial than the 6D.
Hope that helps
Here's a good comparison too:http://www.etherpilot.com/photo/test/misc/6d_5d3_d600.jpg