Light Illuminates, Shadow Defines
Text and photos copyright Charles Glatzer, all rights reserved

My success as a commercial photographer has been characterized by my ability to see and understand light. Wildlife photography is the same without exception. Being able to see and understand light, its quality and quantity, physical properties, etc., and how they relate to your subject and capture medium will allow you to take control of your imagery.

Light quantity, quality and direction should be assessed independently, although together they render the image. The amount of illumination determines the exposure, while the quality and direction of the light source relative to my position renders the scene and subject as viewed.

Side lighting is what provides the necessary shadow detail so important to making the subjects appear three dimensional on a two dimensional surface. The apparent reduction of fine detail rendered has much to do with your position relative to the light source. The closer you are to the light source axis (light directly over your shoulder), the greater the subsequent loss of shadow detail.

What visually separates the white feathers of an egret? Fine shadow. Eliminate the shadow, and you have no apparent separation of feathers, and thus a loss of fine detail. Add to the reduction of shadow the compression of the subject via super telephotos and you lose more of the 3-D effect.

This way of looking, of course, is subjective and not meant as the definitive way to do things. However, in order to progress visually, I believe it is imperative that you be able to recognize how differences in lighting and lens selection can affect apparent sharpness, dimensional quality and an image overall. You should also note for reference that a shadow is rendered 180 degrees opposite the light source, and that fine details and images overall appear sharper on days of greater contrast. And, most assuredly along with lighting, composition plays a key role to an image’s overall visual impact and success.

I recommend you place a stuffed toy animal with fine fur detail on a table a few feet away from a window. As you move your position relative to the subject, notice how light affects the definition of fine details. The closer you move to the light source (the window), the less shadow present and fine detail rendered on the subject. As you move your position more to the side of the subject placing the light further off axis, the greater the degree of shadow present and fine detail rendered on the subject. You need only turn your hand directly to a light source and then 90 degrees from the source to see a significant difference in detail. It is common practice when photographing a model (head shot) to use a ring-light or multiple lights set close to lens axis to negate shadows and thus facial imperfections. It is thereafter the job of the make-up artist to contour the face, adding highlight and shadow via make-up to produce the illusion of dimension on a clean shadowless canvas. Conversely, for male portraiture, the lights are often placed off camera axis to emphasis character and facial detail.

Once you have established your position relative to the subject and light source, it becomes necessary for you to additionally pay critical attention to the subject's position relative to the light source. It is paramount that the subject's face and particularly the eye be oriented toward the light, lest the subject's face be in shadow. With flat lighting (light over your shoulder), the subject's orientation is less problematic as the subject will be evenly illuminated regardless of which way it turns. As a result, flat lighting can produce a higher percentage of keepers, although, in my opinion, the images produced will appear less dimensional to the viewer.

Note: on a sunny day or moonlit night the light source can orient both vertically (higher or lower to the horizon) and horizontally (left or right) relative to the subject. This means that on a sunny day between 10 PM - 2 PM the light is high in the sky and off axis relative to most subjects on or near the ground.

With side lighting and to maintain consistency, it is best to expose for the highlight, the side of the subject that is illuminated. When shooting a sidelight subject in sunlight, my exposure remains the same, sunny f/16 or equivalent plus or minus compensation to render the subject as desired. Remember, when a subject is side-lit, a portion of the subject is in shadow, and this shadowed area will be rendered under-exposed when metered as suggested above, especially when minus compensation is applied for white highlights.

This is where fill flash comes in, and it is an integral part of this method’s success. By varying the amount of flash compensation, you are able to control the degree of shadow detail rendered independent of the ambient light. The key lies in subtly brightening the shadows without obliterating them. Our goal is to effectively compress the overall image brightness/tonal range to that of the capture medium, so that you can capture detail in both highlight and shadow without sacrificing one or the other.

More than any single tool, flash has expanded my creativity and productivity. Flash is an integral part of my image making process, and I now shoot images in light never before considered. Through its use, I am able to control the degree of subject detail rendered, independent of the ambient light and its direction. Proper flash use can afford the nature photographer unprecedented supplemental illumination control and creativity. However, that is another article.

For now, carefully observe how light illuminates and shadow defines the subtle details on your subject. Being aware of the lighting direction relative to the subject will most certainly enhance your unique vision. The little things can often make the biggest difference in your imagery.

Charles Glatzer, M.Photog, a NatureScapes.Net columnist, has been a full-time professional photographer and teacher for more than 25 years; he owns and hosts "Shoot the Light" Instructional Photographic Workshops throughout the USA and abroad. His images are recognized internationally for their lighting, composition and attention to detail. For more information on Chas, please visit his website at www.shootthelight.com.

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