Lighting Observations, Lighting Terms

 Lighting Observations, Lighting Terms

There are commonly used terms that describe lighting conditions and how they relate to both photographic "seeing" and camera technique. The aim here is not to categorize the miraculous, but to suggest ways in which you can capture the subtlety and nuance of light in a wide variety of conditions. 

There are some terms that will be abbreviated throughout this entry: WB=white balance settings on your camera. ISO=Light sensitivity settings. CWA=center-weighted averaging metering pattern setting. Biasing refers to the area of brightness that should be taken into most consideration when making light readings. Bracketing refers to adding +/- exposure to the read light.

In photography, light is often defined by its source

Natural Light: Primarily from the sun. The intensity, color temperature and contrast is infinitely variable, as are the influences of reflection, transmission, and diffusion: all can change the perspective and mood within the scene.

The middle afternoon sky was clear, thus no influence of the color cast of light is evident. An exposure reading was made from the upper right corner of the frame and then locked for this composition. Copyright: George Schaub 

Ambient Light: Also referred to as "available" light", this term generally applies to low light scenes that usually require a higher ISO setting and/or slow shutter speed (depending on widest lens aperture). 

Here, this store display was photographed at night through the display window using the interior lighting as the sole source. The circular lens shade was placed very gently against the pane to eliminate reflections and help steady the camera. ISO was set at 800 to capture a wide range of illumination.

Copyright: George Schaub

Artificial Light: Illumination provided by filament or fluorescent bulbs, strobe (flash) or any other battery or mains powered lights. On-camera flash generally provide automatic output, though testing is encouraged. WB should be set on Auto, although for more refined results consider a "custom" white balance tailored to the light source (see your instruction book for more). For pro or studio strobe a handheld light meter comes in very handy. 

Auto white balance setting held record a "natural" look of the lights of New York's Times Square. ISO was set at 800 as the widest aperture on this fisheye lens was f/5.6. Copyright: George Schaub

Light is also defined by its character, where mood and sense of time and place are defined.

Hard Light: Hard light creates high contrast and deep shadows. While challenging in some ways it is an exciting light to work in, given you know how to control contrast. It can be directional, meaning it comes to the scene from an oblique angle. It can also be ambient, especially at high altitudes or when the sun shines brightly on a snow covered landscape. Knowing what information to "feed" the metering system is important, as biasing the exposure toward the highlight means rich values with less danger of overexposure. Exposure bracketing is good practice, with spot or CWA on the brighter area. 

There is a lot of graphic potential within "hard light" scenes, especially when the reading is specific to the highlight area. Here, a spot reading was locked on the yellow hull in the background. Note how the red brace in the foreground stands out as  counterpoint within the frame. Copyright: George Schaub

Soft Light: Often diffused by fog or overcast sky, soft light can be surprisingly color rich as the medium through which it light passes makes for a soft, ethereal glow on select subjects or the overall scene. Contrast is low, so experiment with exposure bracketing, plus and minus, to add to the effect.

The "afterglow" effect occurs for about 20 minutes after the sun sets below the horizon and provides a wonderful soft light for any subject or scene. Often thought of as primarily an effect for nature scenes it also works well for city skylines. These scene was bracketing -1EV. Copyright: George Schaub

Warm Light: Warm light generally refers to a color cast in the yellow/amber side of the spectrum. It can emanate from the low angled setting sun or even from a tungsten bulb in a room. While the instinct or even the right choice  may be to switch to Auto WB to eliminate the cast, photographing warm light scenes using the Daylight WB settings maintains the perceived light in the scene.

Daylight WB setting maintains the warmth of the setting sun on these redwoods; using Auto may have "balanced" the cast but for me would have sacrificed the mood. Warm balance images tell the viewer about not only the subject but the time of day in which the picture was made. Copyright: George Schaub

Mixed Light: Choosing Auto or Daylight WB, or even setting a Custom WB, can have a major affect on scene rendition. Auto will tend to find a solution that may or may not appeal; warm will create the above-mentioned amber cast, while a Custom WB, will allow for a wide range of rendition options.

Here's an example of mixed color casts, warm and cool (or bluish). The setting sun was sending golden rays flat across the horizon while an approaching mountain storm (untouched by the rays of the sun) recorded in the blue range. Both recorded correctly as the way I saw the scene at the time. When I want to record color casts as I saw them I use Daylight, not Auto, WB. Copyright: George Schaub

Light's Direction: Light can also be defined and exposed according to the direction from which it originates and, of course, the point of view of the photographer. 

Backlight: This is when subjects fall within their own shadow. You can also use backlight to create a bright background for an object or subject, then use flash to illuminate the foreground. 

Taken at sunset with the lighthouse between my camera and the sun, a perfect silhouette is formed, with the lantern passing the light between its structural ribs. Copyright: George Schaub

Side Lighting: Side light occurs when you place yourself at somewhere between a 90 and 45 degree angle from the light source. Sidelight can occur right after dawn or near dusk when the light travels across the surface of the earth. When exposing, concentrate on the brighter areas using CWA or even spot metering pattern and if the light's challenging don't hesitate to bracket.

Side lighting presents both challenges and great rewards when done right. Here I made two exposures, one using CWA metering and the other spot reading, and then exposure lock after each reading. One exposure (CWA) incorporated the sky but included some of the ground, while the other (spot) reading was made off the golden light on the field. The CWA image worked best, as it averaged out the brighter sky area and created nice shadows. The spot reading was great for the field and barns, but overexposed the sky somewhat. Remember, with digital you have to control the highlights, as you can "dig" into the shadows during processing later. Copyright: George Schaub 

 

Color Vision 6: The Eye and the Camera

Your eye and your camera "see" differently. The eye roams around and focuses on many points within its field of view—it is constantly active and any peripheral vision limitations are compensated for by a simple turn of the neck. The camera only “sees” in rectangular frames, and focus is fixed on one plane, modified by the depth of field you set via aperture choices. Its peripheral vision is determined by the focal length you choose when using the zoom, or with primes (fixed focal length lenses), by the focal length of that lens.

The top photo was made with "default" or factory settings of the camera. While fairly true to the cast of light on that day, it lacks the "punch" of rich colors created by choosing a "saturated" picture control. Knowing how you want to interpret a scene points you in the direction of making certain settings that will communicate the emotional qualities of the scene you want to express and bring the image more into line with how your mind interprets it.

The colors you record depend upon the prevailing cast of the light under which you photograph, and how you set the color balance accordingly. The eye adapts and constantly balances color, regardless of the source of illumination. For example, a white shirt will be seen as white regardless of the color cast (unless it is very strong), even under artificial light. If you do not adjust color balance (known as white balance) in your camera under, say, incandescent light, it will record as much warmer than the eye sees.

The eye dilates and constricts to adjust for changes in brightness, and while color reception is lessened in low light, that adjustment is automatic. When photographing, we must adjust the ISO according to the light level. That’s because at the moment of exposure the aperture and shutter speed settings record  the energy of the light in one fixed pulse.

In short, the eye/mind is both receptor and active participant in perception, while the sensor in a digital cameras reacts to and records light according to set rules of exposure and sensitivity.

The difference between these two exposures is in white balance settings. The top image was made using "daylight" white balance and one below is made on "tungsten" white balance. Recognizing color casts and changing them to match what the eye sees (top) and what the camera records is an important aspect of aligning what the eye and the camera sees.

The above may seem obvious, but one of the factors in making images with a camera is that we cannot presume that the sensor will respond to what we see in the viewfinder, regardless of the circumstances or lighting conditions. Understanding how the two differ in their response to light, and how we can modify camera functions to make them more in tune with what the mind perceives (and interprets) is one of the most important, and perhaps least understood and appreciated aspects of photography.

The eye (and by that I mean the mind and eye combination) is an amazing instrument that continually sends messages to the brain, where they are woven with other impulses to form images, the codes that form our perception of the world. By comparison, the camera is a light sponge that captures and holds different brightness values and colors. In short, the camera is a machine. We ascribe value and connotation to those brightness values later, when we view the image as a representation of something we previously saw. Again, the eye is active, the camera is passive and requires our active and creative intercession to blend perception and interpretation within our image.

Next posting: The mechanics of image recording.