Table of Contents
Key Light
In studio photography, the photographer has his own autonomy in the use of light. Basically, you can change the light orientation, intensity, and nature of the key light “as you want”. The quality of the light source, that is, the color temperature, is constant, and it is only necessary to unify the color temperature value of the photosensitive medium and the color temperature value of the light source. Under normal circumstances, the position of the main light is determined after the positions of the camera and the subject are basically determined.
Regardless of the orientation of the key light, it is in a “dominant” position. Otherwise, the lighting effects of several light sources will conflict, cancel each other out, reduce the styling effect, or create messy shadows.
The determination of the direction and angle of the key light is based on the photographer’s modeling needs for the model, that is, to reveal the appearance, highlight (or conceal) certain features, surface structure, color or texture, etc.
Studio flash photography light people picture. The main light is a slightly soft side light with soft paper. When using light, it is necessary to consider the expression of the character’s expression, body and other shapes. It is also necessary to pay attention to the texture and layered performance of the white clothes, and that it will not overlap with the white background tone, giving the characters a space position.
Key Light Changes
If the power of the key light source is insufficient or the projection area is insufficient, two (or more) light sources can be used for the key light. But the closer the light position, the better, and it can play the role of a main light source. But pay attention to the connection between lights and the processing of multiple light sources to form multiple shadows.
Digital cameras have optional high sensitivity. So that many scenes in the case of low illumination, the photosensitive medium can also obtain sufficient exposure. This allows photographers to shoot in relatively low light conditions.
It should be noted that in this light condition, it is difficult for the human eye to judge the brightness of the light and the color temperature of the main light. The determination and setting of the color temperature (white balance) of the key light, the mastery of the metering method and the exposure amount are best obtained through experience.
The use of key light changes a lot, especially in indoor artificial light photography, the key light changes more. Photographers may wish to compare photos of a person or scene with different lighting conditions from time to time to help understand the function of light and master the use of light.
To a large extent, the key light determines the exposure of the photosensitive medium. In digital camera photography, the color temperature of the key light also determines the setting of the manual white balance color temperature value.
Auxiliary Light
Also known as supplementary light, it is used to make up for defects or insufficient light in the main light. In light modeling, it can reduce the light contrast of the subject, increase the level and texture, adjust the tone or tone of the picture, and complete the composition.
The different brightness ratio (light ratio) and distribution of the auxiliary light and the main light directly affect the contrast and tone of the picture, whether it is bright or thick.
In natural light, when the key light (sunlight) is in backlight or metering, the shadow part of the scene is thick, and the dark part lacks gradation. At this time, it is necessary to provide auxiliary light in the dark part, often using a reflector or flash. In fact, under natural light conditions, there is another kind of auxiliary light, which is the mutual reflection of various scenes in the space and the scattered light of the sky. This is also a fill light for shooting natural landscapes.
Position and Brightness of Fill Light
In artificial light photography, the auxiliary light is generally located on both sides of the camera. Too far from the camera will cause a splint light (bright sides, dark center) effect. The height should be parallel to the optical axis of the lens as much as possible to avoid the shadows formed by the main light.
The light is mostly diffused light, and the light is soft to reduce unnecessary shadows. For some parts that cannot be taken care of by the auxiliary light, a second auxiliary light can be added to make up for it. In artificial light photography, the number of light sources should be minimized to reduce the number of shadows. Even soft light can produce faint shadows, and the handling of shadows is a big problem in artificial light photography. We will discuss it again in the control of light.
The fill light is always less bright than the key light. Too bright will dilute the modeling effect of the key light, and too dark will not be able to express the level well. For example: in general, the ratio of the brightness of the main light to the auxiliary light of the character is 1:1.5–1:3. Of course, the light ratio depends on the photographer’s expressive intentions. Looking back at Figure 4 above, the picture is in strong contrast and no fill light is used.
Fill Light and Auxiliary Light
For studio flash photography, the ratio of the main and auxiliary light of the characters is controlled at about 1:2. The main light side is about 45 degrees, and the elevation angle is about 40 degrees. The fill light is located near the camera, slightly above the lens. The fill light takes care of the shadows formed by the main light, so that the shadow levels are expressed.
Since the character faces to the side, the nose shadow formed by the key light is small. There is also a backlight on the right side to enhance the contours and layers of the black hair. The bright light makes the background white, and the background can also be treated separately if it is to increase the effect.
Use of Secondary Light
When photographers take side-light or back-light photography in the morning or evening, due to the excessive light contrast of the scene, the dark scene forms a silhouette. In order to express the level of the dark part without sacrificing the level of the bright part, if there is no possibility to increase the brightness of the auxiliary light, the method of adding a gradient gray mirror in front of the mirror can be used. This reduces the brightness of the bright parts, and relatively increases the brightness of the auxiliary light.
In addition, some people listed the secondary light as the fill light. Sometimes the secondary light plays the role of fill light, but there is a difference between the two. Strictly speaking, it is not accurate enough. Because it is rarely used, I will briefly talk about its function. Secondary light – relative to the main light, it can also be called the transition light of the main light.
One or more secondary lights can be used, as required. Its position does not exceed 60 degrees left and right of the camera position. And the angle is horizontal to 30 degrees. Neither the fill light nor the secondary light affects the exposure.
Backlight
We have already talked about “light direction” and “light angle” in the front. Backlight refers to the light projected from behind the subject in the direction opposite to the camera lens.
There are many problems in application, especially for beginners or lovers of photography. It can’t be said to be abuse, at least it’s used inappropriately. For example: I have seen people photographed with backlight. And the ratio of the brightness of the fill light to the backlight is not appropriate. And the picture loses the atmosphere of the backlight.
Backlighting is a powerful light in photography. If used properly, it can play a valuable role in the picture.
The Role of Backlight
Basically it can be summed up as follows:
One is that it can outline part or all of the subject and form an outer contour line to distinguish the subject from the background. As shown in the figure below, if there is no backlight, the black clothes will be mixed with the background of the same color. This is also an illustration of the effects of all backlighting.
The second is that it can shape the outer edge of the subject and show the outline of the edge. See the picture below, if the subject is not backlit, they can be distinguished from each other by the thorns on their outer edges and the color of the sphere. Backlighting makes their edge shapes and contours stand out. It not only shows their texture well, but also highlights the undulations and lines of the subject’s shape. This strengthens their three-dimensional sense.
The third is that the color brightness and saturation of the subject that can have a certain light transmittance in the backlight can be improved. This can show their outline, detailed characteristics, texture and translucency. As shown below.
Fourth, the backlight can enhance the rendering of the ambient atmosphere and the depth of the picture. Especially in the morning and evening, low-angle backlight is used. Because the backlight is reflected and refracted by fog or dust in the air medium, the brightness and color of the scene we observe have changed. From front to back, the scene changes from dark to bright, color saturation from high to low, color from dark to light, and lines from clear to turbid. This creates a sense of depth in the space and presents a specific environmental atmosphere. See the image below.
Problems That Should Be Paid Attention to When Using Backlight:
In our daily life, as long as we observe people, objects and scenery a little, we will appreciate the light effect of backlighting under natural conditions. Some photographers don’t like backlighting, which shows that they don’t understand enough about the shape of the light.
But not all situations require the use of backlighting. For example, if there is a light contrast or color difference between the subject and the background, it isn`t necessary. If the backlighting angle is close to 90 degrees or not suitable, it is worse than not at all. Because the effect produced is unnatural, giving people a false or even ugly feeling.
The halo or halo caused by backlighting is really beautiful. However, this kind of beautification expression method cannot be abused. And the expression should be combined with the subject and the theme. Also, prevent lens flare from causing the entire image to be foggy.
In addition, soft light can also be used as backlight (generally, backlight is hard light). Its brightness and darkness are determined in the contrast of the main light, mainly based on visual effects. Not directly related to exposure determination.
(To Be Continued)