Creators of the Wallace & Gromit series used a 50x cell phone microscope to film this short—which also happens to be the world's smallest. It revolves around Dot, a girl who happens to be only .35 inches tall!
More information on the film's set-up, via Popular Science:
Animators at the UK studio Aardman used a 3D printer to make 50 different versions of Dot, because she is too small to manipulate or bend like they would other stop-motion animation characters. The figurine's tiny features stretched the limit of the printer - any smaller and it would be hard to make distinct limbs. Each one was hand-painted by artists looking through a microscope.
Directors Ed Patterson and Will Studd attached a CellScope to a Nokia N8 12-megapixel camera to film Dot's struggle in her microscopic world. They said Nokia commissioned them to make the film in celebration of CellScope's potential to improve medicine in the developing world.
[via Popular Science]