Basic knowledge of photographic light

The so-called "photography" is to shoot some parts or all of the scenery and attract the audience with the beauty of the unique characteristics of the subject. The following is the basic knowledge of photography light that I have carefully sorted out, hoping to help everyone.

1, smooth, also known as "front light".

Illumination of light projection and camera shooting direction. When the illumination of the subject is uniform, the shadow of the scene is covered by itself, and the tone is soft, which can hide the bumps and wrinkles on the surface of the subject, but it will be dull if it is not handled properly. Split lighting is not conducive to the performance of atmospheric perspective effect in the picture, and the performance of spatial stereo effect is also poor. In contrast and contrast, it is not as rich as the side backlight. The benefits of smoothing are not only the soft tone, but also the inherent color effect of the scene. Dark smooth light is often used as auxiliary light or modeling light when dealing with light.

2. Side light (oblique side light).

Photographic lighting when the horizontal direction of light projection makes an angle of about 45 degrees with the camera lens. In photographic art creation, it is often used as the main modeling light. This kind of lighting can change the brightness of the subject. It shows the three-dimensional sense of the subject well. Surface texture and outline, and can enrich the dark level of the picture, play a good role in modeling.

3. Side lights.

The projection direction of light is about 90 degrees from the shooting direction, and the objects irradiated by side light have obvious dark edges and projections, which has a strong expressive force on the three-dimensional shape and texture of the scene. The disadvantage is that it often forms too eclectic semi-bright and semi-dark hue and gradation, and often forms uneven scenery of large scenes. This requires that the proportional relationship between the scene and the shadow on the light receiving surface should be considered when composing the picture.

4. Side backlight.

Also known as backlight and backlight. The light projection direction is about 135 degrees horizontal to the camera shooting direction. Most of the scenery illuminated by side backlight is in the shadow, and the illuminated side of the scene is often sharp, which can better express the outline form and three-dimensional sense of the scene. This kind of lighting can better show the perspective effect of the atmosphere in location photography. When using side backlight for close-up and close-up, it is generally necessary to provide auxiliary lighting for people to avoid too dark face, but the brightness of auxiliary lighting should be controlled to avoid affecting the natural lighting effect of side backlight.

5. Backlight: also known as "backlight".

The light from the back of the object can only illuminate the outline of the object, so it is also called side light. There are three forms of backlight: front backlight, side backlight and top backlight. In the case of backlight, most scenes are in the shadow, and only the outline of the photographed scene distinguishes this scene from another scene, so it has distinct layers and can well show the atmospheric perspective effect. This kind of light is often used to shoot panoramic and distant views, which gives the picture a rich sense of hierarchy.

6, ceiling light.

Illumination of light from above an object. Under the top lighting, the horizontal illumination of the scene is greater than the vertical illumination, and the brightness range of the scene is large, lacking the middle level. Shooting people under the top light will produce unusual effects, such as bright forehead, black eye socket, drooping nose shadow, prominent cheekbones and shadows on both cheeks, which is not conducive to shaping the aesthetic feeling of the people. If the auxiliary light is used to improve the brightness of the shadow to form a small light ratio, a better shape can also be obtained. In landscape photography, if the shooting position is appropriate, good tone effect can also be obtained. Top light includes front light, top light and top light. The first two lighting effects are similar, and the latter lighting effects are similar.

7. Footlights.

Light that illuminates a person or a scene from below. The front light is called forefoot light, which forms a bottom-up projection and produces an abnormal shape. It is often used as a light source in performance pictures, such as oil lamps, table lamps, bonfires and other natural lighting effects. Or it can be used as a modeling method to depict special characters, special emotions and render special atmosphere. It can also be used as a facial decorative lamp. The foot light behind the scene is called the back foot light. This kind of light shines on people's hair, especially women's long hair, or the details of the scenery, which plays a role in decoration and beautification. It is often used as effect light in studio shooting.

What is light?

Light is a magical thing. I don't know what the world would be like without light, but without light, there would definitely be no photography, because photography is exposure.

The light we are talking about is actually only a short segment in the spectrum of electromagnetic rays. X-rays are so profound that so far, human science has not been exhausted. There are infrared rays, radio waves, ultraviolet rays, gamma rays and so on in the radiation spectrum, which are invisible to our naked eyes. What we can see with the naked eye is what we call light.

Electromagnetic rays are not static, but constantly vibrating. Wavelength-the distance from one peak to the next, which determines the classification of light.

The distance between two peaks, measured in nanometers and nanometers, not only determines whether we can see these rays, but also determines the color of the rays. For example, light with a short wavelength (about 400 nanometers) is blue-purple, while light with a long wavelength (700 nanometers) is red. All the colors in the middle are the colors of the rainbow.

It turns out that the colors of the rainbow are arranged according to the wavelength, which is amazing!

There is something even more amazing. What if all the colors in these rainbows are mixed together, including the middle color? It turned white. Note that we are talking about light here, not colored pigments. )

The spectrum is usually divided into three equal parts, that is, the so-called three primary colors of red, green and blue. Mix them equally to form white light. If it is not equal mixing, no white light can be added.

So, since mixing can achieve a certain effect, can we use this to filter the color of light?

Of course, for example, if we put a filter in front of the light, only the three primary colors of red light will pass through and the blue and green will be absorbed. Then, when blue and green are mixed together, they will become the complementary color of red. A transparent substance can transmit its own color light and absorb its own complementary color light. An opaque surface reflects its own color and absorbs its complementary light.

Haha, it's too profound, remember? Ok, just remember the following: red light, green light and blue light, which we call primary color light.

If any two kinds of light can be added to produce white light, this color light is called complementary color light. For example: red+green = yellow, green+blue = green, blue+red = product.

This kind of absorption, transmission and reflection of light is very important in photography. Of course, we beginners can also consider it less complicated and regard it as white light. However, these basic principles of light still need to be mastered. Only by mastering them can we know the function of light and what factors will affect its color, and then we can take very beautiful photosensitive photos.

The action of light

It goes without saying that you can't see at night, but you can see clearly during the day.

Why can we see things? Because there is light. There is no light in the object itself, because when light hits the object, we can see it. Therefore, the brightness of an object is determined by two factors, the intensity of illumination light and its ability to reflect light.

It's not hard to understand. For example, when we hit an object with light, we may only see the outline of the object when the light is dim. And when this light is very bright, we may be able to see the details of the object clearly. On the other hand, light with the same brightness hits different objects, a black object and a white object, and the result is different, because black absorbs light and white reflects light.

So when light shines on an object, there will be three situations: absorption, reflection and transmission. The darker the surface, the more light it absorbs. The brighter the surface, the less absorption. For example, when we shoot the venue, if the background is velvet with deep color, then the absorption of light is very obvious. For example, under normal circumstances, 5.6 aperture is enough. At this time, it may be necessary to put 2.8 aperture to ensure sufficient light.

When shooting, you will notice that if the object you are shooting is close to the background color, the subject of the photo will not stand out. Therefore, in order to highlight the main body, it should be considered that if the background color is dark, a brighter main body should be used to increase the contrast. There are exceptions, such as taking high-profile photos.

The reflection of light is the effect of light shining on an object. As mentioned above, dark objects absorb more light, while brighter objects absorb less light and will reflect most of it. Different objects have different reflection effects. The reflection of a relatively flat object is regular, how to reflect it back. Irregular objects, however, have completely different reflection effects, which will break the original angle and scatter in all directions. The rougher the surface, the more scattering.

Transmission, that is, light passes through an object. For example, if a glass is filled with half a glass of wine, the following will happen when the light hits, and some of the light will be reflected back, because the glass will reflect light; A part is directly transmitted through the glass; Some of them may come into contact with wine, but they will not spread. Of course, light will be refracted, and it will change direction when it is obliquely incident from a medium with a certain density to another medium. For example, if we put chopsticks in water, we will think they are bent.

Reflection: Light shines on a smooth surface, and it is reflected at the same angle as the incident angle.

Light falling on a rough surface is irregularly scattered.

C transmission: when light passes through transparent media with different densities at a certain angle, it will be refracted on the surface.

D transparent materials will absorb some light and let other light pass through.

Light passes through the scatterer and becomes scattered light.

Light can be focused by using a lens or condenser.

Mirrors and reflectors bend light. For example, when we take a portrait, we will use a reflector to shine light on people's faces, and the light will form scattered light after being distorted by the reflector.

D bowl lampshade can concentrate and control light.

Opaque objects block the passage of light. For example, taking a silhouette of a person in the sunset is based on the principle that people are opaque and block the passage of light.

F opaque objects divide light into patterns. For example, the windows of ancient buildings block the light and form patterns.

Extended data:

First, the classification of light

There are many classifications of light in photography. Understanding light from different angles will lead to different classifications:

1, from the light itself: it can be divided into hard light and soft light.

Strong light, also known as direct light, refers to direct light, characterized by strong light.

Soft light, also known as indirect light, refers to the light formed after refraction, reflection and scattering, and is characterized by soft light.

Direct light and reflected light not only refer to sunlight, but also include light simulated by lighting equipment.

2. Understand from the function of light: it is divided into main light and auxiliary light.

Main light, the light that plays a major role in shooting a picture, is called main light, which is characterized by light occupying most of the space of the picture.

Auxiliary light, the light that plays an auxiliary and secondary role in shooting a picture, is called auxiliary light, which is characterized by its small proportion of light in the picture, but it plays an important role.

The ratio of the intensity of the main light and the auxiliary light is what we often call the light ratio, that is, the ratio of the brightness of the main light receiving surface of the subject to the brightness of the shadow surface in the picture. The light ratio plays an important role in the contrast of photos.

3. Understand from the position of light, object and lens: forward light and backward light.

Shunt light: the light when the lens is located between the light source and the subject is called shun light, which is characterized by bright picture and sufficient light on the subject surface.

Backlight: the light when the subject is between the light source and the lens is called backlight, which shows that the picture is dark and there is not enough light on the subject.

Of course, smooth surface and backlight are only two extreme representatives of this classification. If subdivided, there are side light and top light.

4. Understanding from light source: natural light and artificial light.

Natural light: The natural light source in nature is called natural light, which generally refers to sunlight. It is characterized by a single light source and its own characteristics.

Artificial light: The light source formed by artificial lighting equipment is called artificial light, such as lamp, candle, flashlight, etc. It is characterized by various types of light sources, each with its own characteristics.

5. Flash and continuous light

Flash: the light that lasts for a short time when shooting is called flash, such as the flash on a mobile phone. Its characteristic is that the light flashes intermittently, which affects the metering of mobile phones and easily leads to inaccurate exposure.

Continuous light: the continuous light provided during shooting is called continuous light, such as sunlight and most of the light sources we usually see.

Second, the three characteristics of light

We all know that light has three characteristics or attributes: intensity, quality and direction. The different attributes determine the different light and the different photographic effects. Let's take a look at three characteristics of light.

1, the intensity of light

Light intensity is the illuminance of light. The higher the light intensity, the brighter the subject, and the clearer the details such as color and texture of its surface.

The intensity of light is directly proportional to the energy of the light source. The higher the energy of the light source, the higher the light intensity and the brighter the subject.

The intensity of light is inversely proportional to the square of the distance from the light source. The farther away from the light source, the lower the light intensity and the darker the subject.

For example, when the brightness of the light source is doubled during shooting, the corresponding light intensity is also doubled, that is,1ev; Brighter; However, when the distance between the camera lens and the light source is doubled, the light intensity becomes one quarter of the original, that is, it becomes 2EV darker.

In nature, the intensity of light will change with the season, time and so on. For example, spring and summer illumination is relatively strong, and autumn and winter illumination is relatively weak; The light will be very strong at noon in a day, and it will be very dark in the morning and evening.

In the process of taking photos with mobile phones, too much light will lead to overexposure, and insufficient light will lead to underexposure, which we need to avoid as much as possible in the process of taking photos. For the specific solution, please refer to the article "Advanced Chapter 3" in my column "Photography Skills in Strong and Weak Light Environment".

2. Color temperature of light

We use the absolute temperature of a complete radiator equal to or close to the color temperature of the light source to describe the color temperature of the light source. A simple understanding is to use absolute temperature K to represent the color of light at different temperatures.

Light with different color temperatures will show different colors and cause different emotional reactions. Accordingly, we can simply divide light into three types, one is warm color light, the other is cool color light, and the middle is warm white light, which is also a term we often use in photography.

Warm color light, the color temperature of warm color light is below 3300k K K. At this time, there are more red and orange lights in the light, which will give people a warm, comfortable and lazy feeling, so it is also called warm color light, and the picture taken is called warm color.

Cold light, the color temperature of cold light is above 5300k K K. At this time, there is more blue light in the light, which will give people a feeling of cold silence, so it is also called cold light, and the picture taken is called cold tone.

Warm white light, the color temperature of warm white is between 3300 K and 5300 K. At this time, the light is pure and bright, which will give people a pleasant and positive feeling.

In "Characteristics and Application of Light in Different Time Periods of the Day", we have talked about the difference and application of light color temperature in different time periods of the day. For example, the cold light before sunrise and after sunset; Warm light at sunrise and sunset; And warm white light during the day. Learning to observe and use color temperature is also a compulsory course in photography.

3. Direction of light

The direction of light, that is, the irradiation direction of light source, is the positional relationship among light source, lens and shooting subject in photography.

Different positions of the three will form different shooting lights such as front light, side light, backlight and top light. Photographs taken along the light have bright pictures and clear details; The photos taken by backlight will be more dreamy and beautiful; The subject of sidelight shooting will be more layered. Photographers need to choose different light directions according to the effect they want to shoot.

Light is ever-changing, where there is light, there is shadow, and recording light is photography. Mastering the basic concept of light, observing and shooting more in actual shooting and using light flexibly are the basis of photography creation.