Harry Potter and the Half-Blood Prince
Warner Bros. Pictures
Loch Shiel is used as the backdrop for the Black Lake in which Hogwarts School sits at the edge of. The visual effects team from the films use multiple shots of other nearby lochs to make the final composite but the main base is Loch Shiel. It can be seen in many exterior shots of the Castle throughout the film series however is most notable at the end of the "The Philosopher's Stone" and "The Half-Blood Prince".