• 📷 Vertical — optical axis within 3° of straight down
  • Less geometric distortion (uniform scale)
  • Used for: planimetric maps, topographic maps, orthophotos, DEMs
• 🎥 Oblique — optical axis > 3° from vertical
  • More distortion (foreground big, background small)
  • Covers a larger area in one frame, shows terrain relief

Mnemonic: nadir is dead-center, oblique is at an angle.