3. Take a photo, press the “magnify/reduce” button immediately after the LCD start to display the picture just taken
My recollection is consistent with the other posters. If I'm looking at the automatic 2 second review of an image on the back of my 5D2, I can't do anything with it (magnify) nor can I move to another image. I have to enter the "play" mode. If you can now magnify the review image immediately after shooting then that is improved functionality compared to the 5D2.