Jim, can you explain how the aperture changes the picture?

By itself (see note below), if you adjust the aperture to a larger number (example: F22) this will allow LESS light to the sensor because the aperture is smaller. A smaller F number (F2.8) will allow MORE light to the sensor because the aperture is larger. LESS light means a darker exposure, MORE light means a lighter exposure. Also, a larger F number (small aperture) will give you a greater depth-of-field, whereas a smaller F number (large aperture) provides a shallow depth-of-field.

Note: If the camera is operating in anything other than Manual mode, when you adjust the aperture, the camera will adjust the shutter speed to give you an optimal exposure.


Here is an example of shallow depth of field caused by a large aperture, F2.8:


Also, can you explain how the shutter speed changes the picture?

Again, by itself (see note below), if you adjust the shutter speed to a larger number (example: 1000) this will allow comparatively LESS light to the sensor because the shutter is open 1/1000th of a second. A smaller number (60) will allow MORE light to the sensor because the shutter is open a longer time, 1/60th of a second. Again, LESS light means a darker exposure, MORE light means a lighter exposure. Also, a shorter shutter speed will freeze action, whereas a longer shutter speed will show motion blur.

Note: Again, if the camera is operating in anything other than Manual mode, the camera will automatically adjust the aperture to give you an optimal exposure in combination with the shutter speed selected.

Following is an example of a slow shutter speed balanced by a small aperture, 1/10 second at F16:


>>>Remember the dual balancing effect of adjusting the aperture and the shutter speed: to arrive at the same optimal exposure, smaller aperture is matched with a longer shutter speed and vice-versa: larger aperture is matched with a shorter shutter speed (usually done automatically by the camera)