Certified Professional Photographer (CPP) Practice Exam

What does photographic reciprocity imply about light intensity and exposure time?

1. They are independent of each other

2. They are directly proportional

3. They are reciprocal

4. They do not affect image quality

The correct answer is: They are reciprocal

Photographic reciprocity refers to the principle that exposure in photography can be achieved through various combinations of light intensity and exposure time, maintaining the same overall exposure value. This means that if you increase the intensity of light, you can reduce the exposure time, and vice versa. The term "reciprocal" indicates this mutual exchange between the two variables, which allows photographers flexibility in achieving the desired result. If you have a higher intensity light (for instance, shooting in bright sunlight), you can shorten the exposure time to achieve the same exposure as a lower intensity light (like a candle) where you'd require a longer exposure time. This relationship is foundational in understanding exposure settings, as it allows for creative control over how a scene is captured based on the available lighting conditions. In summary, the concept of reciprocity underscores the interdependent relationship between light intensity and exposure time, allowing photographers to leverage this relationship to produce well-exposed images across varying lighting scenarios.