Fraenkel Gallery
49 Geary St., Union Square
Jeffrey Fraenkel opened his eponymous gallery when he was just 24, and over the course of the last 35 years has built his brand as one of the best photography galleries in the country. With a formidable list of artists (he's shown everyone from Sol LeWitt to Diane Arbus, and he handles the estate of Garry Wineograd) and a slew of loyal collectors, he's had an enormous influence on many significant photography collections in the city.