Looking to go to a beautiful beach to take great pictures and relax. Lesser known beach and less touristy.
The two most scenic beaches in San Diego are Coronado Beach (not too touristy in the off-season) and Black's Beach up near UCSD. The latter is not too accessible -- need to walk down a path to get to it. Torrey Pines State Park is also quite beautiful, but takes some walking.
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For a different look, not beach, but great for beautiful scenery, try Point Loma - taking the road branching off to the right (to far west side of peninsula across from Coronado) when you come to the national park entrance. It will wind down to a parking lot where you can then walk along the shore and enjoy little cave-like openings and tidal pools as well as paths along the shoreline.