When you take a photograph of a person or a group depicting expression or emotion that’s a Portrait Photography.
Generally the focus in this case is on the face, but the body can too be considered.
An image will be called a portrait if it:
1.) Captures the personality or essence of a subject. Not just a picture with a person in it. A “clinical” portrait might not attempt to reveal the soul of a person, but it still needs to capture something of that person’s uniqueness — or else it’s not a portrait.
2.) Is staged. While portraits can be candid, even those tend to have some intentionality. The lighting, backdrops, and poses are important, even if they are ad hoc. (Or maybe especially when they are.)
3.) Is commissioned. While this isn’t necessary in a literal sense, in a larger sense portrait photographs are made for the purpose. Someone — the subject, or the artist, or some organization — wants a portrayal of a certain person (or group of people). Even a street portrait of a stranger can fit, based on the photographer’s intention.
What portrait photographers or portraiture photographers aim is to focus on the person’s face. They aim to give emphasis on the face of the person because this will also be the focus or the emphasis of the photograph. This does not mean, however, that the person’s body or even the background will no longer be included. Under portrait photography, these can still be included in the photo by the portrait photographer but again, the focus or the emphasis should be on the person’s face, facial expression and even distinct facial features.
One of the common misconceptions about portrait photography is that it is but a snapshot or a photograph of a person. This is not true. In portrait photography or portraiture, a composed or “rehearsed” image of a person in a still position is captured. This basically means that the portrait photographer would prep the subject and the subject would have a specific position and angle. Of course, the “rehearsal” and all the details surrounding it should be discussed between the subject and portrait photographer beforehand.
Here is another beautiful example of portrait photograph.