A few neat videos on how filmmakers use “forced perspective” to make Gandalf huge and Frodo tiny in movies like the Hobbit. Interestingly, they’re not different clips strung together – rather they use perspective to make one character huge and the other small.
It’s the same technique people use when taking photos like this:
The first clip isn’t embeddable, but shows you how they use forced serspective in Lord of the Rings.
Then two clips further explaining how the technique is done, and showing some photo examples of the technique of forced perspective.