EXIF can give you rough heuristics, but not reliable scene understanding.

Useful clues include:

• orientation: EXIF often records whether the camera was held in portrait or landscape orientation. This tells you camera orientation, not whether the subject is a portrait.
• exposure data: aperture, shutter speed, and ISO can be used to estimate a nominal scene luminance. That can help separate likely day vs. night shots.
• capture time: combine the timestamp with exposure/luminance clues. A dark exposure during daytime may indicate an indoor scene rather than nighttime.
• focus distance: if recorded, a long focusing distance can suggest a landscape/scenery image.
• focal length: this may also hint at subject type, since people often use different focal lengths for landscapes, portraits, and distant subjects.

Limitations:

• EXIF describes camera settings, not image content.
• portrait orientation does not mean a portrait subject.
• day/night guesses can fail for indoor scenes, artificial lighting, or intentional exposure choices.
• many potentially useful fields, such as focus distance, may be missing or inaccurate.

So: EXIF is best for probabilistic tagging, not definitive classification.