How to judge whether an image is backlight or sunlight?

1. According to the classification of illumination modes in camera modeling, due to the different nature of light source and illumination direction, lighting can present different illumination modes, and different illumination modes have different modeling characteristics. There are several common lighting forms of film and television lighting: 1. The light that illuminates the object in the form of plane dimming illumination is scattered light, or direct light but smooth illumination. This lighting form is called planar dimming lighting form. Cloudy lighting is the most typical horizontal dimming lighting. In this kind of lighting, the visual difference between objects depends entirely on the color scale difference of the objects themselves. If it is white light, the color of the object will be displayed accurately. This is a landscape, not a picture. Plane dimming lighting has weak directionality and can produce a flat and soft picture effect. The three-dimensional sense of objects is not strong, and objects with similar tone levels are easy to be confused and overlapped, and only when the tone levels of objects are obviously different can they be easily distinguished. The light source is located behind the camera, that is, lighting along the light. Whether it is direct light or scattered light, as long as it illuminates the object in parallel, it is also called horizontal dimming lighting. Indoor rooms with large windows also belong to plane dimming lighting without projected light input. If you shoot with your back to the door and window, the plane dimming lighting effect is the most obvious. If the camera shoots at a certain angle with the doors and windows, it will produce bright and dark sides. But the light is soft and the contrast is not strong. It is worth noting that if both sides of the optical axis of the camera are illuminated with the same brightness, both direct light and scattered light can form a plane dimming effect (referring to artificial light). For example, the light distribution mode of the studio is still in the form of plane dimming, although the angles are different. 2. The light that illuminates the object in the form of bright and dark lighting is emitted by a direct light source and illuminates at a certain angle with the camera, which is called the form of bright and dark lighting. You can see the bright side and the dark side of the object. It is most obvious when the camera makes an angle of 45- 130 degrees with the light source. The lighting mode of bright and dark light depends on the relationship between light source characteristics, shooting angle and ambient light. The proportion of light and dark faces depends on the light source, the object and its position (angle). The contrast between light and shade depends on the contrast between light source and ambient light. Different light ratios can form different contrast between light and shade. The lighting form of bright and dark light is very ideal for expressing the three-dimensional shape and texture of objects. It can make objects with the same color scale change color scale. The lighting mode of bright and dark light makes the color scale of the scene in colorful changes, which is also beneficial to the expression of spatial depth. This is the most commonly used form of lighting. 3. Silhouette and semi-silhouette illumination forms have the following two situations: ① The background is very bright and the object illumination is very little. For example, taking pictures with bright sky and indoor windows as the background will form a silhouette form; ② The subject is extremely backlit, and this pattern will appear when the illumination of the subject is much weaker than the backlight. This is the case if the subject is photographed against a light source. The difference between silhouette and semi-silhouette lies in the different illumination of the object. Silhouette means that the brightness of the object does not reach the minimum brightness level required for shooting, and the brightness of the semi-silhouette object has a certain reaction to the camera. Silhouettes and semi-silhouettes are both flat and have no three-dimensional sense, so it is impossible to distinguish the details, textures and colors of objects. It can only show the clear outline of the object, but not the facial expressions of the characters. What needs to be emphasized here is that the visual experience of the latter two lighting forms is different from the picture effect taken. For example, if we look at the person standing in front of the window, although the light on the person is very weak, it is sometimes not an outline, because the human eye has strong adaptability to the brightness range, and the camera does not have this adaptability, and can only accommodate the brightness range of 1: 30. 4. Form of effect light Broadly speaking, all light effects are effect light effects. What is embodied here is the narrow sense of effect light, that is, to reproduce the special lighting form in life. Such as car lights, stoves, fires, table lamps, matches, cigarette butts and so on. This leads to the reappearance of effect light. Pay attention to the atmosphere, such as a lantern. The front light should not be too bright or it will be distorted. Second, according to the classification of light irradiation direction, the so-called light irradiation direction refers to the relationship between light source, shooting object and shooting angle (direction). Therefore, the illumination direction changes with the direction of the shooting angle, regardless of the change of the orientation of the shooting object. According to the angle between the projection direction of the light source and the optical axis of the camera, it can be divided into seven types: front light, front light, side light, side backlight, backlight, top light and foot light. Light in different directions has different modeling characteristics, so it is an important task for photographers to select and arrange light in different directions. The lighting characteristics and functions formed by different lighting directions are described as follows: 1. Smooth lighting, also known as plane lighting, refers to lighting in which the light source and camera lens are basically at the same height and are consistent with the camera optical axis direction. The characteristics of smooth illumination are: ① the plane of the object receives the same illumination, and all parts of the object are described to the same degree; ② Only the light receiving surface of the object can be seen, but the backlight surface and projection can not be seen, so the uneven features of the object can be hidden without showing the rough surface texture; (3) The hue and tone of the picture are only distinguished by the color scale of the object itself. The picture level is dull and lacks light and shadow changes, but bright objects have darker outline forms; (4) The color of the picture lacks lightness change, which is the best lighting form if colorful scenery is to be displayed. For example, when shooting in the opera film China, this kind of lighting is used to create a dull color effect. The use of scattered light and multi-lamp lighting can form a smooth lighting effect. Use smooth light as the main light when shooting high-profile pictures. Used as auxiliary light in main auxiliary light processing. 2. Forward illumination Forward illumination, also known as positive illumination, refers to light illumination at an angle of about 45 degrees with the optical axis of the camera. It is the main form of light commonly used in photography and video recording. This kind of illumination can make the object produce the change of how bright and less darkness, so it can better show the three-dimensional sense and texture of the object, and better show the level of the picture. 3. Side light Side light refers to the lighting form in which the direction of the light source is 90 degrees from the optical axis of the camera. Its lighting feature is that the illuminated object is half bright and half dark. Five tones are obvious: highlight, bright, dark, sub-dark and the boundary between light and dark. The picture has rich layers and strong three-dimensional sense. Pay attention to the light ratio when using side light, and the light ratio should not be too large. We should control the illumination of the characters within the scope allowed by the camera to avoid the yin and yang faces. People who show their personality often use sidelights. For example, in The Heroine, most heroines use sidelights as lighting. Side light can show rough surface texture well. 4. Side backlight illumination Side backlight, also known as back side light and reverse side light, refers to the lighting form in which the direction of light source forms about 130 degrees with the optical axis of the camera. It is characterized by lighting effect, and the illuminated objects are getting dimmer and dimmer. There are bright spots on the illuminated side of the object, which can well show the three-dimensional sense of the object and have rich layers. In location shooting, this kind of light can better show the perspective effect of the atmosphere. When shooting close-ups and close-ups, it is sometimes used as the main light and sometimes as a decorative light. It is necessary to determine the light ratio according to the use of the side backlight, so as to avoid a large area of a person's face being too dark and having only one bright line. Side backlight lighting has a strong sense of space, and the picture is rich in color and lively. The exterior of the back hill and the interior of the bathroom are backlit. There is also such a scene in Red Sorghum. 5. Backlighting is lighting with the direction of light source basically opposite to that of camera. Backlight can't see the light-receiving surface of the object, but only the bright outline of the object, so it is also called profile light. In camera modeling, backlight can separate the subject from the background and thus stand out. In environmental modeling, we can increase the air perspective effect and strengthen the sense of space. For example, the location of Hand in Hand, a chicken feather location in a place, often uses backlight lighting to express the beauty of the characters and the level of the environment. Backlight is not good for texture. 6. Top lighting comes from the lighting at the top of the main body, which is called top lighting. The horizontal plane of the scene illuminated by the top light is brighter than the vertical plane. Taking close-up photos of people under the dome light will get abnormal lighting effects: the forehead is bright, the eye socket is dark, the nose is bright, the cheekbones are prominent, and the cheeks are covered into a skeleton. Traditional lighting generally does not require overhead lights to take close-ups and close-ups However, if the auxiliary light is used to improve the brightness of the shadow, reduce the light ratio and dilute the skeleton effect of the top light, better results can also be obtained. Modern lamps consume some people think that the overhead lamp is the lamp that really shows time. On some occasions, the influence of its ugly image is inevitable. 7. The light source of foot lighting is lower than a person's head and illuminates people from bottom to top, which is called foot lighting. The front of the picture is called forefoot light, which projects upwards, producing abnormal modeling effect like top light. In film and television photography, it is often used to show the specific light source effect in the picture, such as oil lamp, desk lamp and bonfire effect. Sometimes it is also used to portray or vilify people with special feelings. Third, according to the modeling function of light-five-light modeling method main light: also known as plastic light, is the main light used to shape people and the environment. The main light comes from the main light source of the environment, and various light sources, including front light, side light, side backlight, backlight, top light and foot light, can be used as the main light. The main light plays a decisive role in the tone, tone and atmosphere of the picture. The main light is the basis of exposure. In location shooting, direct sunlight is the main light. The light in the sky is the main light on cloudy days. The main light plays a decisive role in the three-dimensional shape, spatial shape and texture of the subject. The light through the indoor window is the main light. The main light is characterized by clear directivity. It can show the properties of light, and the main light such as direct light will produce obvious projection. The brightness of the main light is second only to the side light. When lighting with bright and dark light, there is only one main light, and the light ratio is often too large to complete the modeling task well, so auxiliary light is often used. But sometimes in order to pursue special light effects, no auxiliary light, such as silhouette effect, is added. Sub-light: Also called auxiliary light, it is the light that supplements the main light. Used to illuminate the shadow part of the subject, so that the brightness of the subject can be balanced and help the main light shape. Generally, sub-light uses scattered light, and sub-light illumination cannot form projection. Outdoor shooting on sunny days, with sunlight as the main light and skylight and ground reflected light as the auxiliary light. When shooting indoors, the light input from doors and windows is the main light, and the reflected light from walls, ceilings and furniture is the auxiliary light. The chromaticity of auxiliary light is determined by skylight and ground reflected light. The brightness ratio of main light and auxiliary light is called light ratio. The ratio of sunlight to skylight on sunny days is too large, so artificial light is often used as an aid when shooting close-ups of people to form a suitable light ratio. Light ratio is the main factor to form tone contrast. In film and television lighting, the main light is usually determined first, and then the auxiliary light is adjusted. Its application principle is that it cannot be brighter than or equal to the main light. The shadow part of sub-light lighting should keep the nature of shadow, so that the dark part has a certain level. Side light: it is the light that shines relative to the camera direction, and it is a backlight effect. Contour lights play a role in depicting the outline of an object. When the tone of the subject and the background overlap (for example, the subject is dark and the background is dark), the corridor lights play a role in separating the subject from the background. In artificial lighting, corridor lights are often used in combination with main light and auxiliary light, which makes the tone levels of the picture changeable and increases the aesthetic feeling of the picture form. Ambient light: Ambient light is the light that illuminates the living environment of the characters in the play. Indoor and real artificial light is the sum of skylight, background light, foreground light and large-scale display props light. The treatment of ambient light reproduces the environment provided by the artist. Its main functions are: a, creating environmental lighting effects, such as cloudy, sunny, day, night, dusk, dawn and so on. ; B, show the time, place and season of the story; C, foil the subject, highlight the subject, and don't drown the subject in the background; D. create an environmental atmosphere. Decorative lamp: also known as decorative lamp, it refers to the light that modifies a certain detail of the subject. Such as clothing light, eye light, hair, facial details and the light used in a certain detail of the scene. The purpose of using decorative lights is to beautify the main body. The usage is relatively free, and it can be irradiated from various angles. Generally used for smaller lamps, decorative lamps can't show traces and damage the overall lighting effect. In the early days of the former Soviet Union, movies were widely used. Although modern photography and video have not been completely abandoned, they are generally used less. The above five kinds of light, namely main light, auxiliary light, contour light, ambient light and decorative light, are commonly used in early film photography. With the rise of documentary style, some people dismiss these five ways of using light as a way for all five organs to use. Those who use five lamps for lighting treatment are ridiculed as conservatives. In fact, using the five methods is just a method and a skill. There is no distinction between new and old skills, superior skills and inferior skills. The emergence of a new skill only enriches the means of modeling, not completely negates the traditional skills. What should be affirmed is that the natural and true way of using light pursues the reproduction of real light effects in life, making art more real and closer to life. However, it is also extreme to completely abandon the use of five lights. Seeing the usage of "Five Lights" refers to what to do, and there is no need to be dismissed as an old method. The key is whether it is used properly and whether there is a light source. As a skill of using light, the five-light method can't be abandoned. But it can't be used as a unique light consumption mode. Use it truly and skillfully. For example, the side light should be mainly light source, and the decorative lights should not show traces. Another reason why five lights can't be abandoned is that there are indeed five lights in life. If you deny the five lights, there will be no technical terms such as "light ratio" and "brightness interval". 4. According to the concept and effect of lighting, it can be divided into natural lighting effect and drama lighting effect. Looking back at the history of film and television, it is obvious that with the development of film and television technology and art, the concept of light consumption of film and television is also changing. The evolution of the concept of light consumption in film and television has roughly gone through three stages: the first stage is the initial stage of the film, which only considers light consumption from the technical point of view in order to complete the exposure task. The main light source is sunlight, and it does not pursue any modeling and artistic expression effects. This period is called "no light effect stage". The term is about 30 years; The second stage started from the late silent film, especially in the 1930s and 1940s, which was called the golden age of drama and film. Film lighting is influenced by stage lighting, which forms the style of drama lighting effect. At this time, the application of artificial light is emphasized, and the lighting pays attention to the beauty of modeling, so it is called "dramatic light effect" stage; The third stage, starting from Italian neo-realism, advocates shooting with real scenes, using more exterior scenes, using non-professional actors, emphasizing truth and nature in lighting, using little or no artificial light, and emphasizing the real light effect in real life, which is called "natural light effect" stage. Drama light effect is a method and concept of using light. This way of using light emphasizes the shaping of characters and the rendering of environmental atmosphere, and pays attention to revealing the inner feelings of characters and expressing the author's feelings with light. It is a lighting method to realize the specific modeling intention of drama and painting by means of light. It evolved from stage lighting, and its aesthetic standard is based on the beauty of drama and painting. Its appearance is closely related to the history of melodrama, star system and black-and-white movies. Melodrama needs light to express the time and atmosphere of the drama. For example, the establishment of Hollywood star system, in order to attract audiences, producers attach great importance to beautiful actors, actors have the right to appoint photographers, and photographers must take beautiful photos of actors to keep their jobs. Therefore, the treatment of portrait light and ambient light has also become standardized and stylized, with exquisite and gorgeous pictures and skillful lighting skills, and has achieved quite high achievements in the black and white film stage, such as the lighting of the American film Broken Blue Bridge. The drama light utility light method has a profound influence on the world's film and television light consumption, especially on China's film and television photography (mainly feature films). In the early films of the former Soviet Union and Europe, great attention was paid to the dramatic beauty and painting beauty of light, such as Xia Boyang, Government Commissioner, Baltic Representative, Ivan Reddy, etc., which are all representative works of dramatic light effect. After the 1960s, the former Soviet Union experienced great changes. In some films, it is a combination of dramatic light effect and natural light effect, that is, it has the characteristics of both dramatic light effect pursuing plastic beauty and natural light effect being true and natural. For example, Rural Women Teachers, No.41, Flying in the Wild South, Unsigned Letters, etc. Since 1930s, dramatic lighting effects have been used in China films. For example, excellent films after the founding of the People's Republic of China, such as Lin Zexu, Song of Youth, Dead Trees Meet Spring, Nie Er and so on. , are masterpieces of dramatic light effects. The older generation of cinematographers Huang Shaofen (Photographer of Lin Zexu), (Photographer of Asma), Photographer of Song of Youth, (Photographer who lives forever in the fire), (Photographer of Lin Jiabao), and Photographer of Independent Brigade, Wang ... In the hard artistic practice, in the photography creation of these works, he is interested in drama. The dramatic lighting effect has the following obvious characteristics: (65,438+0) Stylistic and hypothetical lighting, independent of the truth and falsehood of lighting, able to assume the light source, skilled in the standardization of lighting technology, and paying great attention to the modeling effect of lighting and beautifying characters. Five-color lighting pursues the sharpness of the picture; (2) Be good at using corridor light, often use it to make up for the defects of actors' faces, and pursue the beautification of characters with light; (3) There is a certain limit to the authenticity, only paying attention to the truth of the main light direction, and not paying attention to the true reproduction of the brightness relationship and the nature of the light source. When the ambient light is unfavorable to the character, use the assumed light source, regardless of the limiting effect of ambient light on the character's light. This is an exaggerated way of using light. Natural lighting effect: the concept of lighting in film and television is constantly changing with the development of film and television technology and art, and this change has brought about changes in lighting methods. In 1960s, with the continuous improvement of color film performance (sensitivity 100-400℃, latitude 1: 128), people further discussed the light consumption. Many Chinese and foreign photographers believe that hypothetical light sources need to be used too much to highlight the main body in black and white films, but they can be used less or less in color films. Color difference can be used to make up for this deficiency. Try not to assume the light source to enhance the authenticity of film art modeling. Subsequently, the natural light effect method appeared. Natural light effect refers to a method of using light with documentary aesthetic feeling. Its essence is to enhance the realism of light use. That is, according to the time conditions provided by the script, such as day, night, dusk, dawn, rainy day and sunny day, it is processed by lighting means to faithfully reproduce the real and natural lighting effect. You can't turn cloudy days into sunny days, and truly reproduce the relationship between nature, brightness and color of light sources. This is the mainstream of film and television art at present. "Yellow Land" and "Story of Autumn Chrysanthemum" are both representative works of natural light effect. Armando, a world-famous photographer (photographers of Days in Paradise, Going South and Mr. and Mrs. Kemmers), opposes the exhaustive method of black-and-white movies (dramatic lighting effects) being transferred to color movies. He believes: "Backlighting was dazzling in the 1940s and 1950s, but it is not allowed now. Because movies have become extremely natural and real. Black and white film can make stylized lighting, because black and white film itself is unreal and stylized. For this reason, contour light and imaginary light source are often used, especially to beautify the actors, so that the character light is fixed in a film no matter what the scene is. Choosing modeling loses the authenticity of light ... I am more and more inclined to use a single light source. I never use the lights that include main light, auxiliary light, contour light, decorative light and background light in color films. The light source must be reasonable, and I take this as the principle. " Journal of Beijing Film Academy 1987. 1. In the long-term artistic practice, Archie has accumulated rich experience in natural lighting effects. He doesn't need the classic lighting of the forties and fifties. His lighting principle is that the light source must have a foundation. This principle has been accepted by photographers all over the world. Kramer vs Kramer's highly life-oriented, natural and fluent photography style and lighting style all reflect his famous saying that "photography is more important than reality". He placed great emphasis on realism and pursued the visual authenticity of light. Therefore, it is called a realistic photographer by the film industry. Characteristics of natural light effect: To sum up, natural light effect is a real, natural and documentary way of using light. This method has the following obvious characteristics: 1. The light effect is realistic and accords with the light effect seen in people's lives. Oil lamps are like oil lamps, and electric lamps are like electric lamps. Indoor natural light conforms to its own lighting law; 2. There is no need to assume a light source when shooting the interior, and auxiliary light is used to reproduce the three forms of outdoor natural light when shooting the exterior. 3. Use more natural light instead of all-in-one lighting. Try not to show traces of artificial light in the picture. The American film Mr. and Mrs. Kemmer, the China film Soul Girl and Story of Autumn Chrysanthemum are masterpieces of natural lighting effects. Among them, the story of autumn chrysanthemum has the most obvious natural light effect. This is related to the documentary photography style of the film, because the shooting method of news film-sneak shot and snap shot is adopted, and it is not convenient to use auxiliary lighting to decorate the exterior. Indoor, there is no need to beautify people with corridor lights. The real and natural lighting effect is very consistent with the actor's life-oriented performance.