don’t let the light get in

Zeiss Box Camera from Engles auction May 2010

Toronto. Cameras are all the same in one sense whether they cost pennies or thousands of dollars: they are a light tight box separating a light sensitive medium from a lens so that any object at infinity is in focus on the medium. The light sensitive medium can be coated on to metal, glass, paper or plastic.

A shutter at the focal plane or in the lens is set to determine the duration of the exposure while an aperture in the lens establishes the depth of field and aids the shutter in deciding the quantity of light hitting the sensitive medium.

In the late 1800s and most of the 1900s, during the time of film material, a shutter was essential for successful exposure. Before dry plates, exposure was in seconds or longer and a lens cap, hat, etc. served instead of a shutter. A bellows or other mechanism allowed the camera to focus on objects closer than infinity.

NB. The title of this post is a riff on the song, “Don’t Let the Rain Come Down“, a 1964 song based on the much older English nursery rhyme, “Crooked Little Man” (which delighted me as a child). This is the calypso version sung by the Serendipity Singers.

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