It is a problem that sometimes occurs - basically the sensor has been placed slightly out of alignment, so it is obviously recording at a slightly angle compared to the viewfinder (which is set straight)
A friend has this problem with his 350d, but since it is so far out of warranty now he just learned to live with it and compensate - either by just shooting slightly squint in the viewfinder, or purposely shooting slightly wider and cropping/rotating to the desired shot.
|Hot Air Balloons Over Bagan by User9320321874|
|Yellow Warbler by LeeS|
from A Big Year - birds
|Waiting for the Parade by tcoker1103|
from - La Vida Loca - (Black and White Street Photography+ A Border)