The Sniper - Dry Run
The movie opens as Eddie Miller (Arthur Franz) aims a rifle from the window of his rented room. A young couple dally on the exterior staircase of a house opposite and Franz takes direct aim at the woman and squeezes the trigger. But the rifle isn't loaded, it's a dry run by Miller to see if he has the nerve to see it through.
Then ... The couple are on the staircase of the 471 - 475 Filbert Street apartment house on Telegraph Hill (map).
and Now ... the house is still there, with a green paint job and a sturdier staircase
Then ... Later in the movie we get a glimpse of Miller's rooming house.
and Now ... this is 450 - 456 Filbert and Miller's room, where he aimed his rifle from, was upstairs on the right.