Toronto. In the early decades of photography, the media were so slow a hat or lens cap worked just fine to control exposures. Lenses were left open or used waterhouse stops inserted into a slot in the lens barrel until the thin multi-blade aperture mechanism became popular.
Until the advent of film, metal or glass plates (and later cut film) were hand changed. When dry plates arrived and “instantaneous” exposures became possible, a simple bladed shutter could be used. For the first time plate sensitizing, exposure and processing were potentially separated by a time beyond that ever known before.
As media sensitivity increased, clock-work mechanisms were designed and sold to allow sub-second exposures. With roll film, the manually exchanged plate holders were replaced by an in-camera means to roll the film on to a new unexposed frame. By the 1930s, the mini-cam rage hit and the popular and very compact 35mm cameras were made and sold. Gears were used to ensure the film was wound as the shutter was cocked, eliminating the risk of double exposure.
Today, we see digital technology everywhere. Sensors replaced film; solid state gizmos replaced gears and the captured digital images were a very lengthy series of zeros and ones saved to RAW and Jpeg files which could be “developed” in the device or downloaded to a computer for correction before electronic printing. Now, even the digital cameras are disappearing, replaced by smartphones. Always close-by, smartphones all have cameras now and their resolution and technology continues to evolve. As they say, the best camera is the one you have ready to take the photograph.