When a photograph has a perfectly clear foreground, mid-ground, and background it is one that has the greatest depth of field possible. This means that the camera is focusing on the subject, but also keeping the entire image sharp as well. This is usually something used for landscape imagery but can also be put to good use in a host of other varieties like portraiture and even macro photography. It is not so simple as pointing the camera and focusing in, however, and a good photographer must come to understand the ways in which it can be accomplished.
How is it done?
The first thing to consider is the aperture of the camera’s lens because this is often something that dramatically affects the depth of field. While many people get a bit confused about aperture, it is helpful to know that the larger the numeric setting, the smaller the opening. When a photographer tells you to “stop it all the way down” they are indicating that you should set the aperture at the highest number possible. This makes the lens opening a veritable pinhole, but it also allows for the greatest depth of field.
This means that the camera is often required to use a longer or slower shutter speed to get the shot, and this in turn often means that a tripod is a necessity. While stopping down the aperture all of the way is not always mandatory for a crystal clear shot, it can often be part of the solution.
If the camera is in a particularly bright setting, such as a cloudless midday scenario, the camera may need some additional help to allow for the depth of field to remain its greatest. Often this comes in the form of a filter, and the most effective is the Neutral Density filter. This absorbs light throughout the visible spectrum and alters the exposure settings without impacting the aperture. This means that the photographer will have to understand how to appropriately lengthen the shutter speed and change the ISO to get the desired results.
It is vitally important to remember, however, that changes in ISO can create something known as “digital noise”. This is a graininess that appears when a photograph taken at a high ISO is increased in size during the print-making process. If the image will be viewed primarily in a smaller format or digitally, the noise issue may not present a problem with sharpness.
