Lecture Notes on ISO

Introduction to ISO

• ISO is a variable setting that controls your camera's sensitivity to light.
• Lower ISO (e.g., 100) means less sensitivity; higher ISO (e.g., 1600) means more sensitivity.

Understanding ISO

• Low ISO: Requires more light for proper exposure (e.g., ISO 100).
• High ISO: Requires less light, allows for faster shutter speeds (e.g., ISO 1600).
• High ISO Benefits: Useful for low light conditions to avoid camera shake and blurry photos.
  • Example: Freezing a bird in flight with a fast shutter speed.
• High ISO Drawbacks: Can introduce image noise (grainy texture).
  • Example: Visible noise in photos zoomed in or blown up.
  • Newer cameras handle higher ISO better.

Practical Application in Photography

• Increasing ISO: Helps in achieving faster shutter speeds.
  • Example: Freezing water droplets with a faster shutter speed by increasing ISO.
• Decreasing ISO: Useful for longer, slower shutter speeds with motion blur.
• Exposure Triangle: ISO, aperture, and shutter speed form the exposure triangle.
  • Shutter Speed: Duration light enters the camera.
  • Aperture: Size of the opening through which light enters.
  • ISO: Sensitivity to light.

Camera Modes

• Manual Mode: Full control over ISO, aperture, and shutter speed.
  • Best in controlled environments (e.g., studios).
  • Requires constant adjustment and monitoring.
• Bulb Mode: Extends exposure time beyond 30 seconds (e.g., star trail photos).
  • Use external timers or rubber bands for long exposures.

Practical Session on ISO

• Aperture Mode: Changing ISO affects the shutter speed automatically.
• Shutter Speed Mode: Changing ISO affects the range of available shutter speeds.

Auto ISO

• In Shutter Speed Mode: Helpful for adjusting ISO for desired shutter speed.
• In Aperture Mode: Not ideal as it only prevents camera shake, not motion blur.

Conclusion

• Treat ISO as a tool to adjust shutter speed.
• Lower ISO when possible to maintain image quality.
• Next lecture will focus on lighting, an essential aspect of photography.