I am using 5D2 and I used to use T2i and 7D which have same sensor. T2i, 7D, 5D2 have similar IQ for outdoor and low ISO shoots. However, I really see the difference from ISO 400+. T4i has newer sensor, so I guess ISO 400 and 800 might be okay. For me it will still be about 2 to 3 stop difference.Thanks for your thoughts!
By the way you will also have better DoF and wider angle on FF.
Better DoF is a major plus for me. So far, the bokeh I've been able to get has been nothing to write home about.
You said they have similar IQ for outdoor- is there a big difference when shooting indoor with studio lighting?
Historically, I've held back from shooting anything above 400 ISO. I know ISO performance has improved dramatically since the XTi. I've only used the 5D Mark II a few times, but I did notice a big difference. And the Mark III seems to be an even bigger difference.
Basically, coming from an XTi, pretty much any Canon offering within the last 2 years will be a major improvement for me. Since I don't upgrade very frequently, I'm hoping to get something that won't easily make me envious within 2 or 3 years.
I was considering upgrading to a 5D Mark III with a 4Ti as a backup, but that's edging pretty close to $5000, which is a bit more than I'm willing to part with at this time. Maybe a 5D Mark II with a 4Ti as a backup would be more appropriate? I'm curious to see what the high ISO performance and autofocus improvement will be like on the new Rebel compared to the Mark II. Any thoughts on that?