Practical Photography

Last week we saw how aperture can affect the exposure, this week we are looking at how aperture can affect the depth of field.

Depth of Field affects the area that you want to be in focus and look sharp in the photograph, for example you would have a large depth of field for a landscape so the whole composition looks in focus but for a small object or a portrait you would use a smaller depth of field and compromise some of the background or foreground objects being less focused or slightly blurred.

The main attributes to an object or scene appearing sharp (in focus) are depth of field, the aperture, focal lenght of the lens and the distance from the camera to the point of focus. As a rule the depth of field increases as you  reduce the aperture. The longer the focal length the less depth of field you will have to work with, this is because a wide angle lens can has more of a range and can keep something sharp from a mere few feet away to the horizon. Also the closer to the object you are the less depth of field you have to use.