When I view a .CR2 file taken with a Canon 50D, it shows the file in the full 15mp

When I view a .CR2 taken with the 1Ds MkII, the maximum size it will show is 1.6mp

When I press "R", I get the full resolution

Is there a way to have it show the full resolution images without having to press "R" all the time. It works a treat on the 50D shots, but not for the other cameras. I have unchecked the forcing of jpegs in the control panel module, and all other settings make no difference. Got me stumped
