35mm SLR Photo Camera Description
Learn about how a 35mm SLR photo camera works, and how to use camera settings to createbeautiful photographs.
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Photo Camera Description And The Most Important Camera Adjustments
The principle of a photo camera is very simple, as you can see in the example picture below,
when the camera button is pressed the image is projected through the camera lens on the
camera's medium storage, we take the 35mm photo film, for example. The film is a light sensitive
medium which can be impressed by any small amounts of direct light projected onto it.
Shutter Mechanism
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The shutter mechanism of the camera controls when the light can reach the film and for how much time the light is permitted to impress the film. The shutter speed can be adjusted by the photographer from very small amounts of fractions of a second to an infinite time. |
In sunny scenes the shutter can be set at anything from 1/250 to 1/2000 of a second or even
more, while in darker scenes the shutter must be let open for as long it takes to properly
impress the camera medium (film or digital sensor), and this can be one or more seconds
or even minutes.
Lens Aperture
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The majority of 35mm camera lenses have an adjustable internal blade iris which has the function to moderate the amount of light entering to the film, this is called the lens aperture. Aperture controls another important factor in photography: depth of field. |
The depth of field is the area in the front and behind the subject which can be focused or out
of focus, implying a less or greater depth of field in the image. The larger the aperture (smaller
aperture number) the smaller depth of field, and opposite.
ISO Sensitivity
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Another setting that can be adjusted in both film and digital cameras is the ISO sensitivity. The ISO refers to the film or sensor light sensitivity. The greater the ISO, the greater the light sensitivity. For film cameras, there are different ISO sensitivity films that can be used, and with the digital cameras the ISO is changed from the in camera menu, affecting the imaging sensor light sensitivity. |
Increasing the ISO can help the photographer to expose for a shorter time an image (especially
useful for darker scenes), to decrease the camera movement which can affect the image clarity,
but with the cost of image noise.