1. What is a Nits to Lumens Calculator?

Definition: This calculator converts luminance in nits (cd/m²) to luminous flux in lumens (lm) for a lambertian light source.

Purpose: It helps lighting designers, display engineers, and photographers convert between these important photometric units.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Lumens — Total luminous flux (lm)
• Nits — Luminance in candelas per square meter (cd/m²)
• Area — Surface area of the light source in square meters (m²)
• π — Mathematical constant pi (~3.14159)

Explanation: For a lambertian (perfectly diffusing) source, the luminous intensity is proportional to the cosine of the angle from normal, leading to the π factor in the conversion.

3. Importance of Nits to Lumens Conversion

Details: While nits measure surface brightness, lumens measure total light output. This conversion is crucial when designing lighting systems or comparing display technologies.

4. Using the Calculator

Tips: Enter the luminance value in nits (cd/m²) and the surface area of your light source in square meters. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a lambertian source?
A: A perfectly diffusing surface that emits light equally in all directions, following Lambert's cosine law.

Q2: Why is π in the formula?
A: The π factor comes from integrating the cosine distribution of light over a hemisphere for a lambertian emitter.

Q3: Can I use this for non-lambertian sources?
A: No, for directional sources you would need a different conversion factor based on their beam pattern.

Q4: What's a typical nit value for displays?
A: Smartphones: 500-1000 nits, TVs: 100-1500 nits, HDR displays: up to 4000 nits.

Q5: How does area affect the calculation?
A: Larger light sources with the same nits value will produce more total lumens since they emit light over a greater area.