Both are about the cost of watching. Hitchcock's photographer and Fincher's cartoonist are amateurs who cannot stop investigating, whose obsession damages the people nearest them, and who are right without being able to prove it. Fincher inherits the harder half of the idea: that the audience is doing the same thing, and is being invited to enjoy it. Zodiac withholds the confirmation Rear Window grants, which is the whole difference between a thriller and what Fincher made. Filed MEDIUM: a lineage in obsession rather than a stated debt.