Lens and distance change facial geometry
Wide-angle front cameras can exaggerate near features and compress far ones. If you shoot too close, nose and mid-face can look larger while jaw definition appears weaker. A longer distance with consistent framing is usually more stable.
Lighting and angle reshape perceived symmetry
Side lighting can create strong shadows that make one side of the face read heavier or less balanced. Small head roll or camera tilt can also shift how eye line and jawline are interpreted in a single frame.
Expression timing adds frame-to-frame variation
Micro-expression changes between shots can move smile, eye tension, and cheek shape enough to alter the final impression. Use burst capture and keep posture fixed when comparing which setup really works best for you.