Depth of Field

The depth of field is the distance around an object that comes into focus, in part, or photography. The depth of field that a photographer chooses to improve a given image is a totally subjective choice as it seeks to strengthen the areas in the given framework.
Three factors play a role in determining

or affecting the depth of field of the aperture of the lens (the degree of aperture of the lens), the length of the lens used and the size of the object (the later includes the distance object is far from being the photographer).
The closest is an object of the lens, the smaller depth of field appears in the resulting photograph. Conversely, placing the camera at a distance from the photographed object will create a greater depth of field. For example, landscape images tend to have a greater depth of field, while the portraits have a minimum depth of field.
Similarly, a smaller aperture lens (lens with smaller diameters) and shorter lengths of both lenses to create greater depths of field.
When looking at a photo, you can recognize the depth of field to note that the picture is fuzzy and imprecise. Fuzzy outer edges exactly where the image loses its depth of field.