This was an experimental shot....I used my 40D + 500mm f/4L + 2X TC II for a total effective focal length of 1600mm !!!
The 40D will not autofocus with this combination so I used live view and manually focused. This Cardinal was about 30 yards away in low light
ISO 1600 f/8 1/160 in AV mode, no flash. If you zoom in it's pretty noisy and probably would not make a good large print but for internet viewing it's not too bad considering I was using manual focus high and very high iso for the 40D.