by Roger N. Clark
The direction and quality of the light on the subject are the most important keys to image impact. The direction and angular size of the light illuminating the subject determines image impact. Harsh light occurs when the direction creates unflattering shadows and texture. The Color of light can emphasise certain colors in an image.
The Lighting, Composition and Subject Series:
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Understanding the angle of light and its effects is key to understanding light, the angle of light and image impact. See parts 2 -5 for details of the angle of light, including phase angle effects. This page describes more advanced aspects of phase angle, and the angular size of the light source that gives rise to harsh and/or unpleasant light versus light making high image impact.
What is Harsh Light?
Harsh light is directional light that produces high contrast images from an unflattering direction. An example is shown in Figure 1. Harsh light affects all subjects, including landscapes (Figure 2), animals (Figures 3a, 3b) and people. It has nothing to do with light intensity.
Examine the harsh light/soft light images in Figures 1 to 3. What characteristics do the harsh light images have? In each case, the phase angle is about 90 degrees and the sun is high so that shadows are deep and making the subjects unflattering. The baby cheetahs in Figure 3a have a phase angle of slightly more than 90 degress, making the subjects backlit and parts of their faces and bodies in deep shadow.
But phase angles near 90 degrees and more are not always bad. Sometimes strong shadows elicit drama and/or power. The male lion in Figure 4 is at a phase angle near 80 degrees, but the shading adds drama to the lion, strengthening his power. In this case, the sun was low in the sky and light reflected from the sky and land to the right, out of frame, filled in the shadow.
Compare the images of the elephant in Figures 1 and 5. Both images are at a similar phase angle (near 90 degrees) but the direction and secondary lighting conditions are different. In Figure 1, the sun is high, casting deep shadows on the elephant, resulting in high contrast and thus harsh light. The elephant in Figure 5 has lighting from the side AND secondary light from bushes to the left out of the frame that reflect light into the shadow, mitigating the high contrast. The difference in direction and mitigating secondary light changes a potential harsh light situation into a strong image with form and texture.
Directional Plus Diffuse Light
While direct sunlight can cause harsh shadows, broken clouds can diffusely reflect sunlight from multiple sources onto the subject, creating pleasant effects. Sunlight can also be transmitted through clouds, filling in dark shadows.
The color of the light is also important. For example, shadows outdoors are diffusely lit from the sky. A blue sky fills shadows with blue light. An overcast sky produces a blue cast (cooler) because the water in clouds preferentially absorbs red light. A low sun passes through a thick atmosphere causing a redder (warmer) color. Add clouds to the low sun such that multiple light sources illuminate the subject, and this can produce dramatic and spectacular effects. However, too much diffuse light can reduce shading so much that form is lost. Some of these effects are seen in Figures 6, 7, and 8.
Direction and the Color of Light
There are multiple factors that influence the quality of light, including the phase angle, diffuse/directional mix, incidence angles, and color. Some of these quality issues are illustrated in Figure 7.
Examine the different views in Figure 7.
Diffuse (Soft) versus Directional Light and the Color of Light
Some subjects may appear better with diffuse lighting. For example, flowers. Flower photography can be great on a cloudy day (see Figures 8 and 9, below).
While a low sun casting shadows can give depth and texture to grand landscape images. not all subjects look good with strong shadows. Flowers are one example. Figure 8 shows two extremes in lighting on flowers. Clearly the shadows and direct sun with specular reflections dominate the beautiful colors of the flowers.
Table 1. Lighting for flower images. All images at 100 mm, f/11, ISO 200, June 5 and 6, 2009. Sunrise was 5:33 AM, sunset 8:25 PM. All images are from in-camera jpegs with the same color balance and stretch except image S, which is raw converted to give a warmer color balance. All images were evaluative metering at -2/3 stop.
The image sequence in Figure 9 shows that images of flowers in direct sun have strong shadows that dominate the image. Specular reflections in direct sun also hides colors and masks subtle shading seen under diffuse lighting. Diffuse lighting displays a wide color balance range, but that can usually be corrected by recording raw data and selecting the color balance during raw conversion (e.g. compare Figure 9R and 9S). Note how the color of the light changes the perception of color in the flowers. For example, blue sky de-emphasizes reds. Images 9N through 9R have increasing contribution from a deepening blue sky as sunset fades. The images become more blue, and emphasize the blue and purple flowers. Compare image 9S with 9A and 9B. Image 9S was converted to a color balance close to that in 9B, but the bluer sky in 9S emphasizes the blues and de-emphasizes the reds.
The metering for the images in Figure 9 was compensated to -2/3 stop. The reason for this is that strong colors, especially reds, yellows, and blues tend to saturate. The light meter in most cameras is less sensitive to these colors. In the case of the flower images, the red flowers saturated the red channel with standard metering. I monitor the histogram for all colors on the back of the camera to be sure no channel saturates.
Overhead versus Side lighting
As in landscape photography, having the light source overhead results in generally undesirable photographs, especially with the sun in a clear blue sky. Such light is generally very harsh, meaning very directional and for animals and people casts sharp shadows. For example, people's eyes appear in deeply shadowed eye sockets. Figure 10 illustrates this effect with a teddy bear.
Even with the sun low, the angle of the incident sunlight and the camera (the phase angle) are important. As with the flower example in Figure 8, the phase angle greatly influences the lighting effect on people and animals. Figure 11 further illustrates phase angle effects on a teddy bear. At high phase angles, the shadows are strong, but can be dramatic (as shown in Figures 4 and 5, above).
The angle(s) and color of light are important for images with impact. Some subjects can have strong impact with directional light from the optimum direction(s) (e.g. side light), but not other directions (e.g. overhead light). Other subjects are seen and photographed with more impact in soft light. A mix of soft and direct light can occur on partly cloudy days. The color of light also varies with direct sun in a clear sky, to diffuse light from a blue sky with the subject in shade, to rapidly changing colors of clouds illuminating the landscape near the rising or setting sun. Identifying the varying angles of the light on the subject and its color are key to making images with impact.
The Lighting, Composition and Subject Series:
First Published May 5, 2009
Last updated November 17, 2014.