Focal Length Categories

• Ultra-wide: <24mm (100°+ diagonal) - Architecture, interiors
• Wide: 24-35mm (63-84° diagonal) - Landscapes, groups
• Normal: 40-60mm (40-57° diagonal) - Street, documentary
• Short telephoto: 70-135mm (18-34° diagonal) - Portraits
• Telephoto: 135-300mm (8-18° diagonal) - Sports, wildlife
• Super telephoto: >300mm (<8° diagonal) - Birds, distant subjects

Crop Factor vs Perspective Distortion

Important: Crop factor affects angle of view, not perspective distortion.

• Same shooting position: A 50mm on APS-C and 75mm on Full Frame will have the same angle of view, BUT the perspective/distortion will be different because the 75mm was physically the same distance
• Perspective distortion is determined by camera-to-subject distance, not focal length
• Wide lenses appear to distort because you typically shoot closer to fill the frame
• For flattering portraits: Move back and use longer focal length, regardless of sensor size
• Equivalent result: To match the look of 85mm on Full Frame, use 56mm on APS-C and shoot from the same distance