Have to agree with Michelle looks like a shutter problem. There are 2 curtains and they work by exposing a strip of light across the sensor - it does not look like the sync is right and therefore the strip of light is not travelling the full sensor height.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html