The photo shows Coates in a dress in front of two mirrors, but each of the three versions of her had a different pose. One mirror showed her with her arms down, the other mirror showed her hands joined at her waist, and her real self was standing with her left arm at her side. The camera wouldn’t realize it was taking a photo of a mirror, so it treated the three versions of Coates as different people.

Source: A bride to be discovers a reality bending mistake in Apple’s computational photography

Can we trust our cameras?