* Subject and Composition: If the portrait includes more of the subject's body (e.g., a full-length portrait), portrait format makes sense. However, if you want to emphasize the subject's surroundings or include elements to tell a story, landscape (horizontal) format might be more suitable.
* Background: If the background is important and adds to the narrative or aesthetic, a landscape format can better capture it. A vertical orientation might crop out important elements.
* Aspect Ratio: The aspect ratio of the image, and how it will be used, can impact the choice. 16:9 is common for wide screen displays, versus something squarer such as 4:5 or 1:1.
* Personal Style and Artistic Vision: Ultimately, the choice is subjective and depends on the photographer's artistic vision. Experimentation is key to finding what works best for the specific portrait and the desired effect.
* Cropping/Editing Intentions: Will you crop the image later? Perhaps shooting wider than what will be displayed and cropping later to achieve a portrait ratio is better than shooting portrait in-camera.
When Landscape Can Be Better:
* Environmental Portraits: When the environment is crucial to understanding the subject or adding context.
* Group Portraits: Landscape often works better for fitting multiple people in the frame comfortably.
* Action Shots: If the subject is engaged in an activity with horizontal movement.
* Creative Compositions: To use leading lines, perspective, or other compositional elements that benefit from a wider view.
In conclusion: While portrait format is a common and often effective choice for portraits, it's not a universal rule. Consider the subject, background, desired message, and your artistic vision to determine the best format for each individual portrait. Don't be afraid to break the "rules" and experiment.