Certified Professional Photographer (CPP) Practice Exam

What type of filter can help avoid moire patterns during image capture?

1. Anti-glare filter

2. Neutral density filter

3. Anti-aliasing filter

4. UV filter

The correct answer is: Anti-aliasing filter

The anti-aliasing filter is specifically designed to reduce or eliminate moire patterns in images. Moire patterns can occur when fine, repetitive details in the subject of a photograph interact with the pixel grid of a digital sensor, creating unwanted artifacts that can detract from the overall quality of the image. This type of filter works by slightly blurring the image at the sensor level, which helps to smooth out the edges of these fine details. By doing so, it prevents the sensor from capturing sharp transitions that could result in visible moire effects. This is particularly important in scenarios involving textiles, intricate patterns, or scenes with fine line details. Other filters such as anti-glare, neutral density, and UV filters serve different purposes. Anti-glare filters reduce reflections but do not specifically address the issue of moire. Neutral density filters limit the amount of light entering the lens, allowing for longer exposures or wider apertures, and are not designed to manage moire. UV filters were traditionally used to block ultraviolet light and protect the lens, but they do not have any effect on moire patterns either. Therefore, the best option for mitigating moire during image capture is the anti-aliasing filter.