Camera Obscura (San Francisco, California)

Infobox_nrhp | name =Camera Obscura
nrhp_type = nrhp

---

caption = Camera Obscura in San Francisco
location= 1096 Point Lobos Ave., San Francisco, California
lat_degrees = 37
lat_minutes = 46
lat_seconds = 41.62
lat_direction = N
long_degrees = 122
long_minutes = 30
long_seconds = 51.16
long_direction = W
locmapin = California
area =
built =1946
architect=
architecture= Novelty
added = April 20, 2001
governing_body = National Park Service
refnum=01000522cite web|url=http://www.nr.nps.gov/|title=National Register Information System|date=2007-01-23|work=National Register of Historic Places|publisher=National Park Service]

The Camera Obscura in San Francisco is a large-scale camera obscura and is listed on the National Register of Historic Places. It is located near the Cliff House restaurant perched on the headlands on the cliffs just north of Ocean Beach on the western side of San Francisco, California. The Camera and restaurant are currently owned by the National Park Service as part of the Golden Gate National Recreation Area.

History

Camera obscuras, devices which project an image of the surroundings onto a surface using only existing exterior light sources, usually sunlight, have a long history in San Francisco. The first recorded reference to one in the city is from the 1860s in an attraction called Woodward's Gardens. A previous incarnation of the Cliff House was noted to have had a camera obscura on its fourth floor in 1896. This camera obscura was destroyed when the restaurant burned down in 1907.

When the fourth Cliff House opened in 1937, the owner was approached by businessman Floyd Jennings with the idea of adding a camera obscura to the cliffs behind the restaurant. It was installed on the site in 1946 and has been in continuous operation since then.citation|title=PDFlink| [http://pdfhost.focus.nps.gov/docs/NRHP/Text/01000522.pdf National Register of Historic Places Inventory-Nomination: Camera Obscura] |514 KiB|date=October, 2000 |author=Denise Bradley|publisher=National Park Service]

Technology

The San Francisco Camera Obscura projects an image onto a horizontal viewing table via a reflected image from a viewpoint at the top of the building. A metal hood in the cupola at the top of the building slowly rotates, making a full revolution in about six minutes, allowing for a 360º view around the building.

Light enters the building via an angled mirror in the metal hood. It then passed through a lens with a 150 in. (381 cm) focal length and is projected onto a parabolic white "table" in a black room. The origin of the lens is uncertain but it appears to have been part of a telescope, likely manufactured by the Clark Lens Company of Cambridge, Massachusetts.

Preservation

The Camera Obscura was added to the National Register of Historic Places in 2001 for its engineering significance. While the exterior of the building was extensively modified in 1957 to appear as a giant camera, the internal workings of the camera obscura, the basis of its placement on the Register, remained unchanged since its erection in 1946. The 1957 external architecture was due to be evaluated for historical significance upon reaching fifty years of age in 2007.

References

External links

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