I need a new body: 7D or 1D Mk III?
I'm sure this is a topic that gets posted here relatively frequently but search didn't help and the only comparison thread I saw in the last few months was 1d4 vs 7d. I am in need of a new body; my 40d just isn't cutting it anymore and I've been looking to upgrade. I don't have the cash or open credit line to afford a 1d4 so that's out of the question but second hand 7d's and 1d3's are pretty close cost-wise and I'd like some advice on which way to go. I still feel a bit of regret for getting the 40d when I found out I could have just got a 1d2 for about the same money and I'd like to avoid the same mistake. I'd be shooting primarily birds, natch, and I'm mostly looking at better low-light performance. Is the iq, f/8 focusing and 45pt AF worth paying a bit more for, or is the reach, expanded ISO range, more modern processor and extra pixels a better deal?
Related question about lenses: I currently have a 400mm f5.6 prime and have been thinking of selling it and replacing it with a 300mm f2.8 + extenders. Is this a good option for someone with a relatively limited budget? It seems like a good combination of versatility and reach but I don't know if IQ would suffer greatly with the tele's.