Certified Professional Photographer (CPP) Practice Exam

How does sensor size affect depth of field?

1. Wider sensors decrease depth of field

2. Larger sensors increase depth of field

3. Sensor size has no effect on depth of field

4. Smaller sensors provide shallower depth of field

The correct answer is: Wider sensors decrease depth of field

Wider sensors indeed decrease the depth of field, making them an important consideration for photographers looking to achieve a specific look in their images. When using a larger sensor, the circle of confusion—the area where points appear sharp—becomes larger for a given aperture and distance to the subject. This results in a more pronounced effect where only a limited plane is in focus, thus reducing the depth of field. In practical terms, when you use a wide sensor, such as a full-frame sensor, at a given aperture, you will find that the background blurs out more than it would with a smaller sensor, provided that other factors (like focal length and subject distance) are kept constant. This quality is often desirable in portrait and macro photography, where isolation of the subject is key. While other options present varied interpretations of how sensor size influences depth of field, understanding the relationship established by larger sensors leading to a shallower depth of field is essential for photographers aiming for creative control over their imagery.