1. What is ISO Sensitivity Value?

The ISO sensitivity value represents a camera sensor's sensitivity to light. It's a crucial parameter in photography that affects exposure and image quality, with higher ISO values allowing for better low-light performance but potentially increasing noise.

2. How Does the Calculator Work?

The calculator uses the ISO sensitivity formula:

Where:

• \( H \) — Illuminance at the film plane (lx·s)
• \( Lux \) — Scene luminance (lux)
• \( t \) — Exposure time (seconds)

Explanation: The equation calculates the ISO value based on the relationship between illuminance, luminance, and exposure time.

3. Importance of ISO Calculation

Details: Proper ISO setting is essential for achieving correct exposure in photography. Understanding ISO helps photographers balance between light sensitivity and image noise.

4. Using the Calculator

Tips: Enter illuminance in lx·s, luminance in lux, and exposure time in seconds. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical ISO range for cameras?
A: Most cameras range from ISO 100 (low sensitivity) to ISO 6400 or higher (high sensitivity), with professional cameras reaching ISO 102400+.

Q2: How does ISO affect image quality?
A: Higher ISO increases sensor sensitivity but also increases digital noise, while lower ISO produces cleaner images but requires more light.

Q3: What's the relationship between ISO, aperture, and shutter speed?
A: These form the exposure triangle. Changing one requires adjustment of the others to maintain proper exposure.

Q4: Is native ISO better than expanded ISO?
A: Native ISO ranges (typically 100-6400) provide best quality. Expanded ISO (higher or lower) may reduce dynamic range and increase noise.

Q5: How does ISO differ between digital and film?
A: Film ISO is fixed per roll, while digital ISO can be changed between shots. Digital ISO is more flexible but shares similar exposure principles.