Certified Professional Photographer (CPP) Practice Exam

What lighting ratio is achieved when the main light is one stop greater than the fill light?

1. 2:1

2. 3:1

3. 4:1

4. 5:1

The correct answer is: 3:1

When the main light is one stop greater than the fill light, the lighting ratio can be understood through the concept of stops in photography. A stop refers to doubling or halving the amount of light that hits the sensor, and a one-stop difference indicates that the main light is twice as bright as the fill light. In terms of lighting ratios, a one-stop difference results in a 2:1 ratio, where the main light contributes twice as much light as the fill light. This means that in practical terms, for every unit of illumination provided by the fill light, the main light provides two units, hence creating that 2:1 ratio. It's essential to recognize that a 2:1 ratio leads to good control over shadows and highlights, lending a natural look to the lighting setup without overwhelming contrast. Therefore, understanding these ratios is crucial for photographers aiming to achieve specific lighting effects in their work.