* Composition: Sometimes a wider, landscape format allows for more engaging environmental context or tells a more complete story by including more of the surroundings.
* Subject: The shape and pose of the subject can influence the best format. A dynamic pose or a group portrait might benefit from a landscape format to accommodate the subjects and their actions.
* Storytelling: A landscape format can be used to establish the scene and create a sense of place, especially if the environment is important to the portrait's narrative.
* Artistic Style: The photographer's personal style and the overall aesthetic they're aiming for can dictate the format choice.
* Intended Use: Where the portrait will be displayed or used can also influence the decision. For example, a portrait destined for a website banner might require a landscape format.