DEPTH CONTROL

The advanced photographer using an adjustable camera has the controls needed to determine how the background in a photo will appear. The control used is the APERTURE. When any lens (including our own eye) is adjusted to a small lens opening to reduce the amount of light entering it the focus becomes shallow. Objects far away no longer focus very well.For man people night time is a time when vision gets worse because of this effect. On our camera this can be used to make an annoying background become simplified and less noticed.  OR it can be used to make the background sharp and clear so that it can be seen clearly.

On the average adjustable camera used in class the photographer has two controls to adjust to get proper exposure. One is the shutter which controls the motion of a photo and the other is the aperture.  The two effect each other. If the shutter is set for a fast time it lets in a small of light which means that the aperture will have to let in MORE light to make up for the loss. Likewise, if the aperture is set to let in a small amount of light, then the shutter will have to be adjusted to let in a LOT of light.  The two work opposite to each other. If one goes up to a larger number or setting (250 changed to 500 on the shutter) the other must go to a smaller number to allow the same amount of light to enter.

On an automatic camera this control is often taken over and a compromise is computed by the camera to get the maximum of both setting.   On a semi-automatic camera when the photogapher can set aperture priority the photographer sets an aperture to get the depth desired and the camera automatically adjusts the shutter to get a proper exposure.  But BE CAREFUL for it might pick a very SLOW shutter that might cause a motion blur.