I've had my 5DII for a about 6 months now and I really like it. But I can't help but wonder whether the new 7D wouldn't better suit my needs.


I do really like the high ISOs that can be used with the 5DII. But in very low light, where AF-assist beams are not allowed, I find that the outer AF points are almost useless. The center AF point still does the business but at f2.8 focus recompose doesn't really work, especially with anything that is moving even slightly. And at other times when the outer AF points do work, I find myself framing the image according to where the AF points are located, rather than according to what I think looks best. Which is annoying, especially as the AF points on the 5DII cover less of the viewfinder than the XXD/7D sensors.


I quite like shooting at gigs etc from which I've got some really good results from my 5DII. But I also like shooting nature and fast-moving things, like birds in flight. In these situations the 5DII's AF is usually OK but I do want a longer telephoto lens for this sort of thing. My 70-200 f2.8L IS isn't long enough, even with the 2x Extender (and of course quality is poor). So if 400mm isn't long enough on FF that only leaves me looking at a bank balance-breaking 500mm f4.


If I were to swap for the 7D, however, I'd be able to use the 400mm f5.6 and have more reach than the 500mm - yes, I know it's not "true" reach with crop sensors (I can crop with my 5DII and get the same results as a 50D), but actually with the 7D it gives near-as-dammit true extra reach due to the new 18MP sensor. Yes, I know there are the limitations of the lens to think about (CA etc) and not just resolution, but still I should be able to get good 500 or 600mm equivalent shots from a 400mm lens.


I don't think I can afford/justify both cameras. Bearing in mind the above, should I swap for the 7D?