The Government Information Center has California census schedules on microfilm for 1850, 1852, 1860, 1870, 1880, 1900, 1910, 1920, 1930 and 1940. Contra Costa, San Francisco, and Santa Clara County records were no longer available when the 1850 microfilm was produced. A fire destroyed the 1890 records and no data for California is extant.
To use these censuses one should have the city and address where the person lived during the census year. Name indexes for 1850, 1860, and 1870 are located at the Government Information Center reference desk. We have enumeration maps for San Francisco only. We do not have the Soundex volumes. The recent 1930 release has an easy locator method. The National Archives and Records Administration has an online database which lists every roll of microfilm in the 1930 census, searchable by over 120,000 geographic locations. It is not a family or individual name index or a digital version of the microfilm.
For more information and help on how to access the census microfilm, consult the staff at the Government Information Center reference desk.