Certified Professional Photographer (CPP) Practice Exam

How does depth of field extend in relation to the plane of focus?

1. Equally in both directions

2. Only behind the plane of focus

3. 1/3 in front and 2/3 behind

4. 2/3 in front and 1/3 behind

The correct answer is: 1/3 in front and 2/3 behind

The understanding of depth of field is crucial for photographers aiming to achieve specific artistic effects in their work. Depth of field refers to the range within a photograph that appears acceptably sharp. The concept revolves around how focus is perceived in relation to the plane of focus, which is the specific area of the scene that is in sharp focus. The correct answer indicates that depth of field is distributed unevenly, typically extending more behind the plane of focus than in front of it. Practically speaking, this means that when an object is sharply in focus, a portion of the area in front of this object will also be in focus, but a greater segment of the area behind it will remain acceptably sharp. This phenomenon occurs due to the optics of lenses and how they render depth in an image. In terms of photographic practice, this understanding allows photographers to make informed decisions about their aperture settings, focal lengths, and how they choose to compose their shots to achieve the desired focus effects. The ratio of 1/3 in front and 2/3 behind is a general rule of thumb that reflects typical behavior of lenses. The other choices either suggest equal distribution or incorrect ratios that do not align with the common characteristics of depth of field as observed in photography.