Which of the following can be metered in order to determine "proper" exposures in a "non-normal" scene?

To determine "proper" exposures in "non-normal" scenes, utilizing a gray card is particularly effective, as it reflects a consistent middle gray tone (approximately 18% reflectance) that camera meters can interpret accurately for optimal exposure. This method is particularly useful in challenging lighting conditions where the scene may not represent an average luminance.

Metering green grass or well-traveled asphalt can also provide a reference for exposure. Both surfaces can be metered; however, their reflective qualities might not always lead to accurate exposure readings, especially when the scene contains a wide dynamic range or when the lighting is not uniform. Grass can appear bright under direct sunlight, which might indicate a brighter exposure reading, while asphalt can absorb significant light and yield a darker reading.

In essence, while metering any of these surfaces can provide insights into exposure, the gray card stands out for its reliability as a calibration reference. Thus, selecting all options acknowledges that while different surfaces can be metered, the gray card is uniquely effective for achieving proper exposure in varied light scenarios.