I just noticed that briansquibb even said that he had a 7D and exchanged it for a 5D2 for picture quality.
You need to read it again - I already had the 5D2 and bought two 7D because everyone was recommending it. The IQ was poor incomparison to the 5D2 so I sold them and bought a 1D4 - this was in september 2011. It is so irritating when people misquote me.
@Ardea You are wrong in everything you say. DxO say that the 1Ds3 is better than the 5D2 up to iso400 which is the maximum I use the 1Ds3 for. Why would I use the 1Ds3 in low light when I have a 1D4?
Why should I tell you what I am shooting@1200 with flash? If I choose to use ff that is my choice - it is the way that Canon is going - hence the 5D3 and the 1DX
You say I should use ff for wide angle - well I have been shooting with wide angle all afternoon as I will be on Friday. On Saturday and Wednesday the long lens will be out.
@Ardea + @Gabriele I may do things which you disapprove or disagree with - but that doesn't make me wrong or you right to flame me because I choose to exercise my right of free choice in how I spend my money
Haven't read you saying you sold one 5D2 for 2 7D (you could have tried just one before getting 2 logic says)...by the way today I've been to the Canon official event where they presented 5D3, 1DX and C300.
The Canon representative himself told me that 5D3 is better compared to a 1Ds3.
Why I want to know what do you shoot at 1200mm f/8 ISO 400 with flash? Well because I'm really curious about this combination and really what kind of pictures would you ever want to take with such a setup.
Still today Canon guys told me about the f/8 focus and the way focus works, they preferred to do it this way because an f/8 sensor is bigger than an f/5.6 thus they wouldn't have been able with the actual technology to stuff so many focus points on the sensor.
What kind of pictures would you take with AF at f/8 1200mm BTW? A 600mm is quite a heavy lens so you'd probably use it on a gimbal head, to subject that don't move too much, so there's the chance you could still use manual focus.
In any case they told me that there's still the chance that the central AF point might still work with some selected lenses even if f/8 (but they didn't tell me which ones).
You seem also not clear about what do you want: do you want speed? Do you want quality? Do you want full frame or crop? What kind of pictures do you take mainly?
Also final thing since you seem blind at the graphs on DxO I'll post them here so you can see how 5D2 has better IQ than Ds3 (as also the canon representative said and like lot of people and tests can confirm).
Why would you use the 1Ds3 in low light when you have a 1D4?
This underlines that you haven't understood that FF cameras perform better in low light: a 1Ds3, a 5D2 or 5D3 are surely better than a 1D4 in low light-high ISO situation.
Here your tests where you can see how 1Ds3 is not better than 5D2: as you can see the 1Ds3 has more dynamic range than the 5D2 only at 100ISO, after that the 5D2 beats the 1Ds...beside the fact the difference at 100ISO is really marginal. This is why you shouldn't look only at the final numbers but at the whole graph.