Certified Professional Photographer (CPP) Practice Exam

A filter factor of 16x represents how many stops of increase?

1. 2

2. 3

3. 4

4. 5

The correct answer is: 4

A filter factor of 16x indicates that the amount of light reaching the camera sensor is reduced by a factor of 16. To understand how many stops this represents, it's important to remember the concept of stops in photography. Each stop either doubles or halves the amount of light that is allowed into the camera. Therefore, starting from 1x light (no reduction), each time you double the light, you move up one stop, and each time you halve the light, you move down one stop. To find out how many stops a 16x factor represents, we can think in terms of halving. Halving the light each time until you reach the factor of 16 is as follows: 1. Halve the light: 1x to 0.5x (1 stop) 2. Halve again: 0.5x to 0.25x (2 stops) 3. Halve again: 0.25x to 0.125x (3 stops) 4. Halve again: 0.125x to 0.0625x (4 stops) Since 16 is equivalent to 2 raised to the power of 4 (2^4 = 16),