Certified Professional Photographer (CPP) Practice Exam

In which lighting condition are photographs at higher ISO speeds more likely to have unwanted pixels?

1. Bright sunlight

2. Moderate indoor lighting

3. Low illumination

4. Overexposed settings

The correct answer is: Low illumination

Photographs taken in low illumination conditions often require the use of higher ISO speeds to achieve a properly exposed image. While adjusting the ISO amplifies the camera's sensitivity to light, it also increases the likelihood of noise in the image—resulting in unwanted pixels. This noise appears as graininess or speckles, particularly prominent in shadow areas, making it a common issue when shooting at high ISO levels in dim lighting. In contrast, bright sunlight and moderate indoor lighting typically provide sufficient light levels, allowing photographers to use lower ISO settings, which help minimize noise and unwanted pixels. Overexposed settings can also lead to different issues, such as loss of detail and highlights, rather than the presence of unwanted pixels due to high ISO. Therefore, low illumination is indeed the condition under which photographs are most susceptible to this issue when using higher ISO speeds.