Which statement about gray cards and exposure is true?

Which statement about gray cards and exposure is true?

• A. A gray card is used to meter the scene so the camera can set exposure that renders neutral tones.
• B. A gray card is used to adjust white balance automatically
• C. A gray card adjusts exposure in post-processing
• D. A gray card changes focal length automatically

Answer: (B)

Using a gray card as a reference lets the camera calibrate its white balance. The card provides a known neutral color and brightness, so when you shoot it and set a custom white balance, the camera can adjust its color temperature to render whites and neutrals accurately under the current lighting. This is why gray cards are prized for color accuracy: they give the camera a reliable target to balance colors, regardless of the lamps or sun in the scene. While gray cards can also inform exposure decisions in some workflows, and they don’t impact focal length, the key benefit described here is enabling white balance adjustment based on a neutral reference.

Using a gray card as a reference lets the camera calibrate its white balance. The card provides a known neutral color and brightness, so when you shoot it and set a custom white balance, the camera can adjust its color temperature to render whites and neutrals accurately under the current lighting. This is why gray cards are prized for color accuracy: they give the camera a reliable target to balance colors, regardless of the lamps or sun in the scene. While gray cards can also inform exposure decisions in some workflows, and they don’t impact focal length, the key benefit described here is enabling white balance adjustment based on a neutral reference.