Certified Professional Photographer (CPP) Practice Exam

The angle of incidence in photography is equivalent to which angle?

1. Diffraction

2. Reflectance

3. Incandescence

4. Radiance

The correct answer is: Reflectance

The correct choice is reflectance, as it relates directly to the interaction of light with surfaces. In photography, the angle of incidence is the angle at which incoming light rays strike a surface relative to the normal (the perpendicular line to that surface). When light hits a surface, the behavior of this light can be characterized by reflectance, which is the proportion of light that is reflected off that surface compared to the incoming light. Understanding reflectance is vital in photography since it affects how subjects appear in terms of brightness and color. For instance, surfaces with different reflectance properties will yield different exposures and tonal qualities in the final image. The other listed terms correspond to different concepts. Diffraction refers to the bending of light waves around obstacles, which can impact sharpness and detail but is not directly related to the angle of incidence. Incandescence describes the emission of light due to heat, and while it pertains to light sources, it does not have a direct correlation to angles in the context of photography. Radiance is a measure of the amount of light that passes through or is emitted, and it also does not specifically align with the angle of incidence like reflectance does.