A non controlled environment. I am coming from a Canon 60d and the noise is terrible above 800 without a speedlite and even then way to noisy. I would hope such a leap to FF and better technology would yield much better results just unsure if the d800 is the way to go or the canon 5d3. So far I have not seen the tremendous noise free 25k iso images in reviews actually I think it drops off at 6400 and continues from there. That's not much of an increase considering they are talking native 25k iso. So I was wondering if nikon was doing the reverse and saying 6400 with a true ceiling of 12800 or at least some very detailed images below 800. I do shoot in all kinds of light so that is why iso is so important. I also need a larger DOF since usually there are more than one person in my shots.
Comparing the 60D to the 5D is like comparing night and day. If the performance jump in all areas is tremendous. hence the reason for you spending $2400 more lol . A 60D is still however more than capable for attaining nice shots if you use a speedlite to compensate for not boosting higher ISO. The better ISO performance of the 5D will only make your job easier in one aspect by giving you more freedom to boost ISO and achieve faster shutter speeds at smaller apertures (thus giving you a deeper DOF or more in focus). In any case, it's still best to use flash if you are able to (i.e. not in a venue where flash is forbidden).
I want a deeper dof than my 60d can offer bringing multiple people in focus and be able to shoot with a faster shutter speed. For example i took a shot tonight indoors with poor lighting of the kids playing on the floor and my speedlite was not handy so i had to shoot 1/15 f4 iso3200 to get them and boy was it noisy you would have thought it was 12,800 and with such a slow speed they hands were blurred from motion. I want to be able to get those shots. So assuming i was using the 5d3 there i would hope to have shot it at 1/60 at least. With an increase in iso of course. I used the 17-55 efs. Yeah i could have used a lower fstop like 2.8 but then it would have been harder to get them in focus as they were not on the same focal distance. Any suggestions as to which camera is right is greatly appreciated.
Your DOF is controlled by your aperture setting. You will need to shoot at a higher aperture in order to get a large group of people in focus. Think of it this way, the 61pt AF system will help you focus more accurately, not increasing DOF and bringing more subjects into focus at the same time. This is where composition comes into play. You need to set your aperture to allow the appropriate DOF in your shot and position the people in such a way that they all fit into the DOF. The ISO performance will definitely help you achieve faster shutter speeds in available light or for shooting over longer distances that flash won't reach.
Now that I understand what you are trying to do, I think it's pretty safe to say that the 5DmkIII will be your better option. BTW, I just received mine and played with it for a bit. I must say, regardless of specs in reviews and comparisons to the 5DmkII; I instantly realized first hand that the 5DmkIII is a beast of a camera!
It's a completely different animal from the mkII (which I also have). So instead of calling the 5DmkIII a merge between a 5DmkII and 7D, it's more like it took the ergonomics of a 7D and merged the 5DmkII and 1DX!
So from initial impressions, I am simply impressed! Canon FTW!