Jaw pain in cold weather

There are many kinds of light, such as frontal light, photometry, backlight, direct light, direct scattered light, silhouette and so on. Appearance, in addition to direct sunlight, there are scattered light from the sky and reflected light from the environment; Indoor, there will be different lights at night. Many different lights constitute the light effect of the environment. In order to simulate the various light effects of natural light and make better use of light to create, we must study the properties of each light, find out their characteristics and similarities and differences, and then use them flexibly. There are three ways to classify light: by light source, by light projection direction and by light modeling function. First, according to the different light sources, all light sources that can emit light can be divided into natural light and artificial light according to their sources. 1. Natural light Natural light sources are called natural light. From the perspective of film and television photography, the available natural light is mainly the sun and skylight. The sun is the main light source. In addition to direct sunlight on the earth, some light is absorbed by the atmosphere and then irradiated to the ground through the atmosphere. This light is called skylight. In recent years, due to the improvement of film sensitivity and the appearance of intensifying lenses, the sensitivity of cameras has been continuously improved, and sometimes the scenes of the moon and moonlight can be directly photographed, so the moon can also be regarded as natural light. In addition, under the sunlight, the reflected light of buildings and walls also belongs to natural light. Characteristics of natural light: strong brightness, wide and uniform illumination range. However, its brightness, illumination angle, distance and color temperature often do not depend on the subjective will of the creator. The intensity of natural light varies with seasons, time, climate and geographical conditions. In a year, summer has the strongest light and the longest available shooting time; Winter is the weakest, and the available shooting time is the shortest. Sunshine intensity is affected by weather changes, and it is divided into eyes, cloudy, gloomy, fog, haze, rain and snow, and its illuminance is also different. The change of geographical conditions also has a great influence on the sunshine intensity, such as the difference of latitude and longitude, the difference of altitude, the difference of illuminance and color temperature. The higher the altitude, the stronger the direct sunlight, the weaker the scattered skylight, the greater the contrast of the scenery, and the sky is dark blue. On the contrary, at lower altitudes, the scattered light in the sky is stronger and the contrast of the scene is softer. The closer to the equator, the stronger the sunshine. The intensity of light received by mountains, flat land, high altitude and seabed is also different. In a day, due to the rotation of the earth, various lighting conditions such as dawn, sunrise, morning, noon, afternoon, sunset, dusk and night are formed, and the characteristics of sunlight in different periods are different. As shown in Figure 6-3, the change of sunshine in one day ① Sunrise and Sunset When the sun rises from the eastern horizon and leaves the ground at an angle of 15 degrees, it belongs to sunrise time; When the sun sets from the west and falls below the horizon at an angle of 15 degrees, it is called sunset time. The light characteristics at sunrise and sunset are basically similar, so the shooting techniques are similar. The characteristics of light at this time are: the sun reaches the ground through the thick atmosphere, and most of the short-wave light (blue-violet light) is absorbed and diffused by the atmosphere, forming a blue sky, so the sky light has a high color temperature and strong brightness, and only the light with a long wavelength (red-orange light) reaches the ground, so the sun at this time appears red-orange light, with a low color temperature, the direct sunlight is weakened, warm and soft, and the horizontal plane (or backlight surface) of the subject is blocked. At this time, the sun is low, and the vertical plane of the scene facing the sun has strong light and high illumination. The horizontal light is weak, so the illumination distribution of the scene is uneven, forming a contrast between light and shade, and the object has a long shadow on the ground. Because of the above characteristics, this moment is the prime time to shoot color films, and the time is relatively short, and the light changes quickly (brightness and color temperature) and it is not easy to master. Usually only one or two shots of the atmosphere can be taken. So this moment is called the effect light moment, and it is also called "golden hour" by some foreign masters. (2) In the morning and afternoon, when the sun continues to rise or set, its illumination angle on the ground is between 15 and 60 degrees, which are morning and afternoon respectively. At this time, the main characteristics of light are: the distance of light penetrating the atmosphere is short, with little change, and the light diffused by light is much smaller than that at sunrise and sunset, so the color temperature of direct sunlight is higher. This period of time is long, the light changes slowly, the illuminance and color temperature are almost unchanged, and the color temperature is about 5600K K K. The vertical and horizontal planes in the scene are evenly illuminated, which has a good expressive force on the face of the character and will not distort the image of the character. Therefore, in location shooting, this period is regarded as the main shooting period or normal lighting time. (3) At noon, the sun rises. The time between the 60-degree angle in the morning and the 60-degree angle in the afternoon is noon time, which illuminates the ground scenery roughly vertically and the horizontal plane is bright. The vertical plane is dark, which makes the vertical plane of the subject in sharp contrast with the sky. Traditional lighting methods think that the light at noon is not conducive to shooting. At this time, the figure is illuminated by the top light, which is easy to distort the image. Under normal circumstances, it is not appropriate to feature people at this time. As long as the panoramic lens is suitable for the scene and the picture has a good level, you can still choose to shoot against the light. For example, shooting a large area of wheat fields and lighting them with overhead lights can get a good level, as long as you pay attention to the contrast with the sky. (4) Dawn and dusk from the east to before sunrise are called dawn; When the sun goes down, the ground scenery is still visible, which is called dusk. At this time, the characteristics of light are: the sun is below the horizon, the sunlight illuminates the atmosphere at high altitude, the ground scenery is illuminated by the scattered light from the sky, and the scenery is in the dark, losing the level of detail and only seeing the general situation; The light distribution is uneven, the horizontal plane is bright, the vertical plane is dark, and everything is a haze; The sky is the brightest part, which is both the light source and the subject. At this time, the contrast between the sky and the ground scene is great, and its brightness range greatly exceeds the tolerance range of film and camera. When shooting, if the exposure is made according to the sky, the ground scenery will appear silhouette. This moment is an ideal time to shoot night scenes, and photographers often use it to shoot night scenes and choose atmosphere shots. The shooting location mainly depends on natural light, and artificial light is mostly used as auxiliary light. Because natural light is limited by many conditions, it cannot be transferred by the creator's subjective will. Therefore, photographers need to observe and master the changing law of natural light in order to choose and use it in combination with their own artistic image. 2. Artificial light The luminous light source made by everyone is artificial light. Such as lamps, reflectors (reflectors, reflectors). Commonly used lights in film and television photography include incandescent lamp, carbon arc lamp, iodine tungsten lamp, halogen tungsten lamp, dysprosium lamp, etc. There are many kinds of reflectors, such as total reflection and diffuse reflection. Artificial light is characterized by low luminous intensity and small illumination range, so the distance between light and objects has a great influence on the illumination range and intensity, but its brightness, illumination angle, distance and color temperature can be manually controlled and adjusted. Using artificial light to create rich picture tones, character modeling and different lighting effects is not limited by season, time, climate and geographical conditions, and can be created calmly according to the artistic conception of the creator. But improper use will distort the image. 2. When determining the positions of the subject and the camera respectively according to the projection direction of the light source, according to the angle formed by the projection direction of the light source and the camera, it can be divided into five types: front light, side light, backlight and backlight; According to the vertical position of the lamp, it can be divided into top lamp, foot lamp and so on. (See Figure 6-4) Schematic diagram of light projection direction in Figure 6-4 1. The height of the fairing is close to that of the camera, they are on the same horizontal plane, and the direction of light projection is the same as that of the camera, which is also called front light. The characteristics of forward lighting: when an object is evenly illuminated, only the light receiving surface (bright surface) can be seen, but the dark surface (backlight surface) can not be seen, and the projection is blocked by itself, which is conducive to eliminating unnecessary projection; The level is dull, and the object has the form of dark outline; The color and tone of the picture are mainly determined by the color of the object itself and the level of light and shade, which can well represent the inherent color of the object, but at this time, the color selection and light and shade configuration of the scene itself are very important; It can fade the folds of the subject, and can't show the concave-convex structure on the surface of the object, which is not conducive to the three-dimensional sense and texture of the subject, and is also not conducive to the perspective effect of shooting multi-layer scenery and atmosphere. The sense of space in the scene is not strong, and the picture looks bland and has no ups and downs, so it is sometimes called flat light. Generally, scattered light is used as pre-auxiliary light, or small spotlight is used as decorative light. Sometimes it is also used as the main light to obtain a soft modeling effect. Front light is often used for light processing of high-profile pictures. 2. The angle between the projection direction of the front light source and the shooting direction of the camera is about 45 degrees, which is called front light or side light and oblique light. The characteristics of front light: the subject has a large light receiving surface and a small backlight surface, which can produce too many tone levels, and can not only see the whole picture of the object but also have a certain stereoscopic effect, which is conducive to expressing the stereoscopic effect, texture and sense of form of the object; The scene will be projected under the front light, which can enrich the picture composition if handled well. Generally, direct light is given priority to, and people are treated from the side, or parts of scenery and people are decorated. The front light is the most used light in photography. 3. The light whose projection direction of the sidelight light source makes an angle of about 90 degrees with the shooting direction of the camera is sidelight. Characteristics of sidelight: Under sidelight illumination, the light receiving surface and backlight surface of the subject are half and projected on one side. Although the object can't see the whole picture clearly, the five color components, such as bright side, sub-bright side, dark side, sub-dark side and the boundary between light and dark, are significant, and the picture has a strong three-dimensional effect. If the surface of the object is rough, realistic texture can be obtained under side light. Sometimes the rough surface structure can be exaggerated, resulting in a strong modeling effect. As decorative light, sidelight can highlight the local details and shapes of objects, such as the light used to decorate clothes. Using side light to illuminate the scene has a large contrast between light and shade and lacks a smooth tone level. Generally, it is not used to represent normal portraits, but it can be used to shoot some special light effects and create a specific light atmosphere when necessary. When using sidelight, we should pay attention to the brightness ratio between the light receiving surface and the backlight surface, that is, deal with the light ratio well. 4. The light whose projection direction of the side backlight light source makes an angle of about 135 degrees with the camera shooting direction is the side backlight or backlight. The characteristics of side backlight lighting: most of the main body is facing away from the light source, and the light receiving surface presents small bright spots, or the outline of the object is drawn to separate it from the background, which is beneficial to the multi-layer scenery and atmospheric perspective, and makes the picture have a certain sense of space and three-dimensionality; In modeling, you can add highlights to the picture, increase the brightness range of the scene, and make the picture lively; When representing characters, it is generally necessary to add positive auxiliary light. If the side backlight is used as the main light, the auxiliary light cannot exceed its brightness, otherwise it will cause false artificial marks. 5. The included angle between the projection direction of backlight and the shooting direction of camera is about 180 degrees. Characteristics of backlight lighting: Under the condition of backlight, the object can only see the backlight surface but not the light receiving surface, which lacks three-dimensional sense and texture performance, but the object has bright outline illumination, which can outline the outline of the scene and make the outline shape of the scene clear; In modeling, backlight can separate the subject from the background, thus making the subject stand out, which is suitable for showing the perspective effect of multi-layer scenery and atmosphere and strengthening the sense of space in the picture; When shooting portraits of people, you can decorate the people with backlight; When shooting an environment or portrait with a specific artistic effect, the front subsidizes the scattered light with different brightness, which can make the picture have different light-dark contrast and produce different effects such as silhouette and semi-silhouette. In recent years, people's faces can also show the texture and tone level of skin in the dark due to the improvement of the film's latitude and the dynamic range of the camera, so people can use the backlight as the main light in combination with the content to obtain more vivid and natural screen images. In real life, the backlight surface of the scene is mainly illuminated by blue sky scattered light and color environment reflected light. Under the condition of modern film and television technology, the color of the backlight surface can be fully reproduced, so shooting under the backlight condition can enrich the color of the picture, which is also the reason why some film and television works are willing to shoot under the backlight condition in recent years. 6. Top light The light projected from above the subject is the top light, which becomes the top light effect when the height of the light source exceeds 60 degrees. The characteristics of the top light: in the environment under the top light, the horizontal illumination is larger and the vertical illumination is smaller, forming a large contrast between light and shade, and the picture lacks the intermediate level of light and shade transition, resulting in a hard tone effect; When taking a portrait, the top of the head, the arch of eyebrows, the bridge of the nose, the jawbone and the upper cheekbone are bright, while the eye sockets, the lower nose and the two clips are dark, and the eye sockets are sunken and the cheekbones are prominent, forming a skull image, uglifying the characters and causing abnormal feelings. Unless there are specific modeling requirements, it is generally necessary to avoid using top light to shoot portraits. When shooting a character Xiao Xiang with a dome light, it is mostly to show a specific light effect or to set off a certain atmosphere. For example, in the movie One and Eight, overhead lighting is often used. Top light is a kind of abnormal light, but in the imitation of natural light, as long as the light ratio is handled properly, it may not necessarily form abnormal effect, and sometimes it can show the real effect of natural light. 7. Foot light The light emitted from under an object is foot light. The characteristics of foot light: the light and shadow structure is opposite to the top light, which can make the subject form abnormal effect and cause abnormal effect, and it also belongs to abnormal light, which uglifies the character image; In the imitation of natural light, it is often used to express specific light effects, such as oil lamp, fire and candlelight. Or to render a special atmosphere, such as horror, adventure, or an ugly character. Footlights can also be used as decorative lights to decorate eyes, clothes or hair. When shooting glass cabinets, pools and other objects, foot light can enhance the three-dimensional sense and sense of space of the subject. Side light, side backlight and backlight can all cause the projection to be too long. If used properly, it can enrich the light form of picture composition, create silhouettes and semi-silhouettes, enhance the beauty, horror and mystery of the picture, render the artistic atmosphere and shape specific modeling effects. Third, according to the modeling function of light, light can be divided into main light, auxiliary light, decorative light, ambient light, contour light, effect light, eye light and so on. 1. Main light When shooting a scene or lens, the light that shows the main light effect is the main light, that is, the light that plays a major role in determining the modeling image of the subject. The main light is the main light that shapes the environment and depicts the characters. It determines the characteristics of environmental light effect, the structure of light and shadow and the shaping of human body. The main light is also called plastic light. All the light levels and attributes mentioned above can be used as the main light, but the modeling effect is different. Generally, the main light is mostly direct light at the side position, because such light is very common in life, such as the sun and lights are above people. It can also express the three-dimensional sense and texture of the subject. The main light must be based on the light source and it is the main light source directly from the environment. The shadow produced by the main light is the only shadow allowed in the picture. The main light is the first light that photographers and lights consider when dealing with light. The main light is determined, which determines the light effect and atmosphere of the picture. After the light level and intensity of the main light are determined, different soft and hard tones, different contrast, different light atmosphere and effects can be created when it is used with auxiliary light with different brightness. When shooting outdoors, sunlight is usually the main light. Photographers can choose to determine the position of sunlight according to their own modeling tasks, which can be positive, lateral or reverse. In addition to shooting night scenes, dusk, dawn and other effects, artificial light is rarely used as the main light when shooting exterior scenes. With the continuous improvement of the latitude of the film and the dynamic range of the camera, photographers like to use sunlight as the main light more and more when shooting on location, and the characters are very vivid, natural and realistic. When shooting animals and flowers, the effect of backlight is more vivid. 2. Sub-light Sub-light, also called auxiliary light, is the light that illuminates the backlight surface that is not illuminated by the main light and plays an auxiliary role in the main light. It determines the texture and hierarchical representation of the shadow part of the scene and helps the main light shape the body. Auxiliary light is generally scattered light, which cannot form a shadow on the object; Auxiliary light can improve the brightness of the shadow part of the subject and dilute the redundant projection, but the relationship between light and shade formed by the main light must be maintained. If it exceeds the brightness of the main light, it will destroy the light effect of the main light in the picture; The auxiliary light should keep the light effect of the shadow. Traditional auxiliary light usually comes from the camera direction. The secondary light simulated by natural light is reflected light based on the environment. In the natural environment, if sunlight is the main light, then the sky light and the reflected light from the ground environment are the basis of the sub-light, while indoors, the reflected light from walls, furniture and other environments is the basis of the sub-light. The auxiliary light may have a chromaticity determined by the ambient color. After the brightness of the main light is determined, the change of the brightness of the auxiliary light and the contrast with the main light can change the contrast of the scene, determine the hardness of the color tone of the picture, and cause different light atmosphere. The ratio of brightness formed by main light and auxiliary light is called light ratio, which is an important factor to determine the sound quality and light effect atmosphere of the picture. In traditional lighting methods, light ratio is an important means to depict characters and emotions. In a movie (TV series) or a scene, don't change the light ratio easily after it is determined. It changes with the development of personality or the change of mood. In modern lighting methods, the light ratio is not so strict, which is determined by the state of light. 3. Ambient light The light that illuminates the subject's environment is ambient light, including the lighting of the background, foreground and surrounding large furniture. Natural light is the main way to shoot exterior and real scenes during the day, and ambient light is determined by nature, direction, time concept, building structure, number of doors and windows, and drama atmosphere. Ambient light is the main part of the film's light effect, and it is an important factor to determine the film's tone, tone, contrast and environmental atmosphere. The use of ambient light is a process in which photographers recreate scenes for artists. It should pay attention to geographical features, time (day and night), climate (cloudy and sunny) and specific atmosphere to create a typical environment. 4. Decorative lights treat and polish some local details of the main body, so that the shape, tone level and color are more perfect. It is called decorative lamp, also called decorative lamp. You can partially decorate your eyes, hair, face, clothes, props and scenery. It can improve the brightness difference of the picture, enrich the tone level, enhance the transparency of the picture and improve the artistic expression of the modeling image. Decorative lights generally use small lights, and their positions are flexible and changeable. It can be based on life or it can be assumed. Starting from the creator's intention, use small lights to outline and highlight plot points, beautify or uglify characters (such as scars, foreheads, chins, jewelry, etc.). ), change the picture composition, increase the transition tone between the main light and the auxiliary light, or use facula, light bar, colored light, rotating light, from bright to dark, from dark to bright, etc. Create a certain atmosphere and complete the artistic conception. When using decorative lights, we should also pay attention to the discretion, which should not affect the light efficiency of the main light, destroy the overall atmosphere, or show off too much. 5. Effect light The light that produces special light effect is effect light. In film and television art, there are two kinds of effect light: partial light source effect light and emotional atmosphere effect light. Light source effect light: there are often several light sources in the environment at the same time. Except the main light source used as the main light, the reproduction of other light sources belongs to the category of effect light. Especially some special light source effects, such as candlelight, desk lamp, small oil lamp, flashlight lamp, lightning lamp, turning on and off lights, driving lights, firelight, water reflection light, etc. Effect light also refers to the light effect in a specific time and space in nature. Such as special time light effects: night scene, sunrise, sunset, dusk and other effect lights. Light effects in specific space: light effects in dark caves, dark cells, etc. If we make good use of the effect, we can create more vivid, natural and real picture modeling, enhance the expressive force of modeling and create a specific artistic atmosphere. For example, in the movie "Flying South in Wild Goose", the photographer grasped the characteristics of special effects on the night of air raid, which not only rendered the panic that the war destroyed the peaceful life, but also set off Vera's painful mood after being insulted and possessed by cousin Boris, leaving a deep impression on the audience. In most cases, the light source effect light is used on the basis of life, but sometimes it can also be used from the perspective of dramatic effect, in order to increase the realism on the screen and some effects and atmosphere in dramatic expression. Emotional effect light: all kinds of special light treatments used to obtain dramatic effects are emotional effect light. For example, in the evening of TV programs, colorful computer lights are used to cause various actions and create various rhythms. %D%A