In photography, the term shutter speed represents the amount of time that the shutter remains open when taking a photograph. Along with the aperture of the lens (also called f-stop), the shutter determines the amount of time light exposes the film or sensor. The shutter is similar to a “curtain” located inside the camera that remains closed until you press the button to take a photograph. The bigger the denominator the faster the speed (ie 1/1000 is much faster than 1/30).The pinwheel below is photographed at different shutter speeds, with a faster shutter speed on the left and a slower at the right. Shutter speed is measured in seconds – or in most cases fractions of seconds.
In optics, an aperture is a hole or an opening through which light travels.
In photography, the aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter speed, the aperture size will regulate the film’s or image sensor’s degree of exposure to light.
A simpler way of thinking about the function of the aperture is think about the human eye. Our pupils act just like apertures by letting in just the right amount of light to see.
DEPTH OF FIELD
In optics, particularly as it relates to film and photography, the depth of field (DOF) is the portion of a scene that appears acceptably sharp in the image. The depth of field is directly related to the aperture setting.
The smaller the number of the aperture gives a shorter depth of field, and the larger the number of the aperture gives a larger depth of field.