Sometimes we are confronted with lighting that either makes it seem impossible to create a great photo, or makes it difficult to figure out which is the best approach. Here is how I handled one such situation.
I was hiking in a parcel of land owned by the Ausable Club which is known as the Adirondack Mountain Reserve when I came across this scene. The lighting was very harsh and low haze and dark clouds diminshed clarity. I liked the composition, but I knew that this was going to be a problem scene to record on film. Because the lighting wasn't optimum, a couple of different approaches could be used to make the image; I could try to create an image where the foreground was exposed properly, ignoring the sky, or expose for the sky, letting the land be underexposed. A split neutral density filter was not useful due to the shape of the landforms, besides, the haze limited any detail that could be seen in the distance.
Image #1 shows the result when I exposed properly for the foliage in the foreground, ignoring the sky. I don't think this image works well due to the fact that most of the image consists of white haze in an overexposed sky. The amount of properly exposed, detailed foliage is minimal resulting in a ho-hum image.
Image #2 shows the result of underexposing the foreground. It's better than #1, but I find that the vague detail in the foreground is distracting and the sky is still lifeless - not dramatic enough to be interesting.
Image #3 is the best of the lot. To get the right exposure to ensure a dramatic sky, I used my spot meter to measure the light relected from a portion of the clouds with that was approximately 18% grey. This resulted in a very dramatic sky, no detail in the foliage, and great lighting on the farthest portions of the lake. Although this image was created in mid-afternoon, the resulting photo looks more like nightfall on the front of an approaching storm. Much more exciting than image #1!
Many people use the term "bracketing" to describe a method of creating different exposures when confronted with a difficult lighting situation. To bracket an exposure, you start with a base exposure, then create additonal exposures at overexposure and underexposure settings. For example, if you meter a scene and come up with an average exposure of f16 at 1/125s, you could bracket at plus or minus half-stop increments by creating the following exposures at 1/125s: f11, f11 +1/2, f16, f16 +1/2, f22. The bracketed images will allow you to choose which exposure you like best.
Bracketing implies some level of unknown. We don't know how a certain part of an image will appear when a certain exposure is made. With attention to exposure differences, we can usually have an understanding of how the image will record on film before we make it. If you are using slide film, the difference in exposure that can be recorded is only about five stops from shadow to highlight; about seven stops for color negative films and even more for most black and white films. Meter your scene and note the exposure differences between the darkest shadows and the brightest highlights. If it fits within the working range of your film, you've got it easy; if not, you have to decide to expose for highlights, shadow, or average. Using a spot meter (hand-held or in-camera) will help you measure the differences in exposure values between important parts of your image. Use the same line of thinking...that is, if the exposure difference is too great, you will not be able to get a great exposure of the entire scene. Either recompose using a different lens or distance from the scene, or create different exposures that result in different looking images.
For the Shutterbugs:
The "Lower Ausable Lake" photos were created with my Hasselblad 500 CM camera, and 80mm lens, Bogen 3021 tripod. Film - Fuji Velvia, ISO 50. No Filtration. Exposures unrecorded, however, there was about one stop less exposure in image #2 than image #1 and approximately 3 stops less exposure in image #3.