Which choice describes the effect of employing a shallow depth of field?

Using a shallow depth of field significantly influences how the viewer perceives the image by isolating the subject from its surroundings. This technique creates a pronounced differentiation between the in-focus subject and the out-of-focus background, allowing the viewer's attention to be directed specifically to the subject of the photograph or film.

The effect is often achieved by using a wide aperture, which results in only a small portion of the scene being sharp while the rest becomes blurred. This method effectively reduces distractions from the background and enhances the emotional or thematic impact of the focal subject.

In contrast, options mentioning enhancing background details, decreasing brightness, or increasing the amount in focus do not accurately reflect the purpose or outcome of employing a shallow depth of field. A deeper focus would result in more detail being visible throughout the image, which contradicts the intended effect of shallow depth.