Canon has some catching up to do with respect to sensor performance as measured by http://www.DxOMark.com. Canon doesn't even come close to the top performing Nikons. (High score is better.):
96 Nikon D800E
95 Nikon D800
94 Nikon D600
81 Canon 5D III
79 Canon 5D II
(The Canon 1Dx is not yet rated.)
What are the chances that one of the reasons for the new sensor in the 6D is to catapult Canon's sensor performance into the mid 90's? I can't see Canon doing that considering the $3,500 EOS 5D III just came out and has a score of just 81. But Nikon's new $2,100 D600 kicks butt with a score of 94!
Sensor performance isn't everything... but, if I were to choose Nikon or Canon today, I wouldn't be choosing Canon.
Are thes numbers linear? 100 Points is two times better than 50 Points?
I don't think so. My 40D has sth. around 60 points and makes very good image quality (cleanliness, plasticity, contrast). The 5Ds produce extremely good image quality with around 80 Points, Nikons have 90-95 Points and produce more extremely good image quality. But I am shure that the difference between 40D and (5Dii/iii + Nikons latest FF models) is obvious for each parameter while the 15 points difference between 5Dii/iii and Nikons models is less obvios and depends on the shooting scenario.
So in my opinion the dxo mark values lack in two terms:
- What does a difference of e.g. 10 points mean in relation to it's starting point?
- Are they measuring the all the parameters and the right parameters which defines image quality for the broad spectrum of applications?
I really like the 2 steps of additional DR which the Nikons have as real advantage. They are - now - the winner in that discipline. But throw away all the Canon glass if Canon will enhance their sensors in the next few years to reach similar DR (I am shure that will happen!)? - NO. it would be wasting of money for me.
Canon has one problem with the current situation: They can buy Sony sensors but perhaps they don't want to do that. Or they have to work around Sony's patents finding another way to increase DR - that's a guess of mine but that's the way things go. Someone has a patent which protects a widely defined technical measure so others have to invent essentially new ways to increase their performance.
That is a chance for us photographers, that Canon has to fight for an alternative sensor concept with increased DR but perhaps a new design that improves other parameters like color fidelity, read out speed etc.
Today the bodies behind the lenses change much more often than the lenses! So I stay calm and observe the market besides taking photographs.