How can you tell that a portrait was shot using a narrow depth of field? If the background is out of focus but the foreground is not visible, the depth of field may have been quite wide?
A.: Yes, this is correct. However, let us consider the practical side of it. To shoot a portrait by using the selective focus technique, the photographer selects a wide aperture to narrow the depth of field and focuses on the eyes of the model. If the eyes are not at the same distance, the camera is focused on the closer eye. This does not mean that portraits are always shot with a narrow depth of field. Imagine a portrait of a person eating a lobster and drinking wine in a restaurant. The disturbing background can be eliminated by selective focus but the depth of field in front of the person must be sufficiently wide to keep the person, the plate and the wine glass in sharp focus. The point of focus is somewhere in front of the person and the depth of field is adjusted to get the person, but not the background, in sharp focus. When a model is positioned against the sky or a smooth backdrop, a selective focus is not needed, unless desirable for a certain pictorial effect.
