About 12 years ago, I took a photography class (that I didn't complete). One of the projects involved photographing a solid black wall and a solid white wall. "Well, that's dumb," I remember thinking, but I did it, anyway. At the time, I didn't understand the point of that assignment until I got the film back - the black wall wasn't black and the white wall wasn't white - they were both shades of gray.
During that same assignment, one of the exposure settings for each of those walls was to be taken using a meter reading from the ground or in a nearby shady spot. Those pictures came out more true-to-life. It turned out, the instructor was teaching us about the way many light meters measure the light as an average of the entire scene to find the mid-tone. Taking the reading from the shade and ground faked out the camera by setting my own mid-tone.
Another way to measure or estimate the proper exposure for such high contrast, neutral-colored scenes is to use a gray card. A gray card is a flat, matte gray sheet of cardboard that reflects 18% of the light shone on it, referred to as incident light. An average scene is thought to reflect 18% of the light that falls on it (though, this is currently up for discussion since studies have shown this is closer to 13%). By using an 18% gray card within the same incident light, the reflected light reading can be measured. Set the camera's exposure to this light meter reading and you've set your own mid-tone which will produce an ideal exposure closer to the actual scene and how you saw it.
To use a gray card to determine the correct exposure of a scene, first set the camera to manual mode. Place the gray card within the scene and orient the card so that it is parallel to your lens. Take a light meter reading of the card. Set the camera's exposure to this reading and shoot.
A gray card can be used with both hand-held and on-camera light meters, though, depending on the type, they may meter differently. On-camera light meters measure light differently based on their type: spot meters use the spot on the center of the ground glass visible through the viewfinder; center-weighted meters average the light in the circular area in the middle of the frame, while matrix/evaluative take an overall reading within the frame. If you're using the camera's on-board light meter, then make sure the gray card fills the area from which the light is measured. If you're not sure, try getting close enough so that the card is the only object being read by the meter and go from there.
Gray cards are available in many forms and sizes that fit in your bag or back pocket, while others can be much larger. I happen to have a photography field guide that included gray cards in the front and back of the cover, so I just tore one out and stuck it in my bag.
Gray cards may be used with both film and digital cameras, though digital cameras also have a middle gray within the file's histogram that can be used to balance the picture in post-processing. Hopefully these tips help you discover a new way to determine the best exposure so all of your photos turn out exactly as you wanted them to.