From Canon's Website
"EOS 650D can not only shoot at the current 3:2, but also can shoot at aspect ratios of 4:3 1:1 and 16:9. This allows users to match the playback environment for displaying the images. Images with any of the aspect ratios also be resized"
It is likely you have set your camera to capture in an other than the stock 3:2 Aspect Ratio. If you are using LR 4.3, you should be able to reset the crop in the develop module to retain the missing areas. Check your camera's settings to make sure you aren't shooting in one these modes.