Building on a recent post from "thepankcakeman" regarding the AF on the 5D Mark II.
I am in the process of switching from Nikon to Canon (I recently sold my D300 and 17-55mm 2.8 lens) and would like to move up to full frame for better low light / higher ISO performance. Looking at the 5D Mark II, but I have read a lot about the poor AF. Most photos I take are of my four year old daughter (unwilling subject and often I shoot at home in low indoor light). Starting from scratch, so lens-wise, looking at a fast prime (50 1.2 or 85 1.2) or a zoom such as the 24-70 2.8. Fine shooting with the center AF versus multi-point.
For those with kids or those shooting action in low light, what has been your experience with the camera? I could wait for a new model with a better AF and suffer with my S95 (nice compact, but much slower/much lower hit rate than DSLR) or buy a low priced model such as a T3i as a stop-gap.
Hmm a Nikon shooter wants to switch to Canon for "better low light / higher ISO performance"?
5DII has excellent IQ and a lot of resolution. This will give you the option to crop your images freely. It's a full frame camera indeed and offers great high-ISO performance. But like it's said over and over again on similar threads, it's AF is not it's best feature, especially if you want to track moving objects. It's is capable but certainly not the best.
Now, you are coming from a D300 which is a capable action camera. So you had 51 focus points and 15 of them were cross-type. This Multi-CAM 3500DX AF system is more advanced than the one you find in 5DII, which has only
9 focus points, only the center point being cross-type. Nikon also uses the same module (3500FX, modified for FF sensor) on their higher models such as D700, D3, D3s etc. Hands down, Nikon has the edge here, if you want more keepers
when you track objects. I am not saying 5DII can NOT track, but for you, because you are coming from a more advanced AF system, it might be a disappointment, giving you instant "buyers remorse". Which brings me to :
Did you consider upgrading to Nikon D700? Full frame like you want, excellent high-ISO performance (arguably better than anything Canon offers at this moment) like you want, and a very capable AF system, again, like you want. Layout, controls, dials, in short ergonomics are all very similar to what you are used to with your D300. AF is virtually the same except for AF points being more cluttered in the center, rather than nicely spread across the frame. If you pair it with good glass, you will get amazing results. Learning curve will also be very steep.
I shoot Canon myself and prefer it's offerings to Nikon's but in your case I don't mind recommending you a Nikon camera, since that one seems more suitable for you.
Now, if you say you actually meant "I want a 5DII for it's great low-light performance AND it's excellent IQ
" (which is way better than on the D700) and you can live with "center AF-point only", then ignore the paragraph above and welcome to Canon.
ps: as wickidwombat rightfully pointed out;
if you wait for a 5d3 i think your daughter will be a year older by the time you get to shoot.
Whatever you decide, get your camera today and start shooting. Time flies...