The area as a tourist I'd be most worried about would be the Tenderloin at most times of the day, and the Polk Street area after dark. Although it's safe for you personally, do exercise caution when you're in the area around the Calumet store (21st and Bryant) as it is still gentrifying and cars do get broken into if you leave things sitting out in view. The Mission district looks rougher than it actually is, but still exercise reasonable caution. Paranoia is not needed. Chinatown is a great area for urban shooting, as is North Beach. If you want to see some parts of town that are very reflective of the "real" San Francisco without looking like postcards, take a drive out Geary Boulevard heading west from downtown. You'll pass through a number of ethnic enclaves including Russian, Greek, Vietnamese and Korean communities. If you want a break from the urban stuff, when you're at the end of Geary Boulevard, just before you get to Cliff House, turn in to the parking lot on the right and take the trail leading away from Geary Boulevard (Land's End trail). You'll walk along the cliff heads with an amazing view out over the Pacific, and maybe 3/4 of a mile or so along, there will be a set of stairs that lead down to the Land's End beach. You can get a nice view of the Golden Gate Bridge from the beach that will be very different from what you're used to seeing. Just a word of caution - Lands End Beach is used by nudists in good weather - that said in the half-dozen times I've been to it, I've only ever seen one person sunbathing nude, and they were being harmless just sitting there. Also worth the trek across the GGB are the WWI/WWII era fortifications in the Marin Headlands portion of the Golden Gate National Recreation Area.