I used backyard as the sort of example that is always made in law school. Backyards are actually not entirely private. Say you have an illegal pool, if the cops

I used backyard as the sort of example that is always made in law school. Backyards are actually not entirely private. Say you have an illegal pool, if the cops see it from the air, you're still subject to prosecution. Or if you shared a backyard with a neighbor and were running around naked when they have free access to the backyard, it's still exposure. What is true is that if you have a 12 foot fence and are in your backyard topless and your neighbor films you, then that's illegal because you had an expectation of privacy. Same goes if someone is being taped in a bathroom. You are in space that's not publicly accessible. I'm not 100% sure where the definitive case law on what is and is not private resides, but most of it is well defined in the physical world. So consider these three things: barriers (walls, space is not public), ownership (I own or are here with consent of who owns), and consent (I agreed to wave privacy rights explicity or de facto i.e. I'm walking down this street). These three things have to be ALL met or else you could tape people taking showers at your house legally. With your apartment, things are even more gray because you don't have an absolute right to privacy there as your landlord can enter the premises under many pretenses.