I dunno why pple say 50D's noise is bad/worse than 40D and that 7D is better. 7D is actually worse (up to 1-stop worse if compared at pixel level) than 550D and 50D (especially at lower ISOs/whether at pixel level or at same size) if scientifically tested in labs. 50D is similar to 40D. The difference between all these cameras are not significant, anyway.