The other day I wrote a post about the excellent 400mm L lens and EOS 1Ds Mk2 combo. The image I used to demonstrate the quality the pair could produce has always been a marvel to me, showing the capability of an older, non stabilised lens and an "obsolete" 16mp camera.
Different images (the new one I stumbled on while cleaning out my library), taken three years apart, in different light and a female, rather than male monkey. Cropping roughly the same, from a slightly out dated OMD M43 camera and budget 75-300mm lens. Just goes to show. Granted the 400mm was used with a tele converter, but the Olympus lens is a slow, cheap zoom. The eye and chin hair detail look to be the same, with both having the appropriate level of processing and I can't help feeling the Olympus colour is more accurate in it's lighting circumstances.
The odd thing is, the current second hand value for the Canon setup is about $2000 au and the Olympus $800.