Three kinds of lights commonly used in photography

Natural light, artificial light and ambient light are the most commonly used light sources when I first came into contact with photography. After knowing the characteristics of light and the equipment at hand, we can adjust the shooting parameters according to the changes of the environment, so as to shoot good works.

1. natural light

The sunshine under normal illumination is stable and abundant, which can create amazing light and shadow changes.

Since the invention of photography, natural light has always been the photographer's best friend and the main learning object of commercial photography lighting. Although we can't control it, learning to make good use of it is the first step to learn photography well.

Natural light includes sunlight, moonlight, starlight and even invisible light, but generally speaking, sunshine is the most important thing in photography. Affected by the distance between the sun and the earth, the position in the sky and the climate, the texture and intensity of natural light will vary greatly at different times of the day.

By analyzing the sunlight passing through the prism, it can be found that the seemingly white sunlight is actually composed of indecomposable monochromatic lights such as red, orange, yellow, green, blue, indigo and purple. However, the light that the human eye can see only accounts for a small part of the spectrum; In addition, there are infrared rays, ultraviolet rays, X rays, gamma rays, cosmic rays, radio waves and other invisible lights.

When sunlight passes through the atmosphere, it will be refracted for the first time, and then it will be refracted or reflected by different objects again, forming the world we see; When we open the camera shutter, the light is bound to be refracted by the lens and recorded by the negative film or photosensitive element to form a photo.

On cloudy days, the light is stable and uniform, and rich details can be incorporated to avoid shadow interference.

Natural light is particularly important for landscape photography. In a day's shooting, if we can make full use of the light effect commensurate with the light and shade, we can make the work attractive in light and shadow. Many photographers think that the best natural light is before sunrise or after sunset. At this time, the sky presents a soft color, which is the most expressive natural light in landscape photography.

Low-angle natural light can produce detailed shadows or projections on grasslands, beaches, water surfaces and hilltops, increasing the richness of images. However, in the light environment such as top light or backlight, the strong contrast and shadow produced by direct sunlight can also take excellent photos of people. Therefore, when shooting outdoors, we should not only firmly grasp the instantaneous light and shadow of the subject, but also always pay attention to the position change of the sun in the sky.

2. Artificial light

When the sun goes down, but there is still light in the sky, it is the best time to shoot the night scene with your hands.

Since the sun dominates the day, the night is artificial light to be the "protagonist".

Although the position of the sun is incomparable, artificial light still plays an important role in photography, which can help photographers create many rich and interesting images. The sun has just set, and there is still a glimmer in the sky, but when all the street lamps are lit, it is the best time for us to shoot without a tripod.

At night, the combination of water and light is wonderful and quiet. Carefully observe whether there is enough artificial light by the lake or river beside you at night, and whether there are colorful light and shadow changes. If the lighting conditions are perfect, you can turn the light and the reflection in the water into your favorite works.

Of course, the night after the rain is also a good time to shoot. Remember to pay attention to the streets around you. It is best to choose an area with many tall buildings. At this time, the road will be a sea of light and color. As long as you write a composition with your heart, you will have unexpected results.

When night falls, we can turn ordinary street scenes into impressive photos by paying attention to the color changes of different artificial light sources and making good use of the reflection effect between rain and light.

When night falls deeply, street lights are the most common theme. If you want to shoot this kind of subject, it is suggested to use a tripod to help stabilize the fuselage, avoid image blur caused by vibration, and shoot dazzling light tracks with long exposure. Remember to choose the main street with heavy traffic and try different angles to get satisfactory results.

When using artificial light source for composition, we must pay attention to the color of light. Because there are many colors of artificial light sources, if they are not well blended in the works, the photo composition will be disordered, but it will be unsightly. If you want to show a big scene with a wide film, it is suggested that you can use a variety of light sources to compose the picture, which will be ideal; However, if you only want to show a small scene, the colors should be few and refined, and try to form color contrast and accurately show the theme.

Indoor, we can be divided into two situations: studio and non-studio. For the non-studio part, it is suggested to adjust the white balance according to the on-site light source (tungsten lamp, fluorescent lamp or color LED lamp); If you are in a studio, you should adjust the light distribution method according to the image requirements.

3. Background light

When shooting only with ambient light, the dim and faint scene atmosphere is successfully preserved.

Unless it is in a studio where the lighting environment can be completely controlled, it is sometimes difficult for us to control the influence of light sources from the environment on the subject when taking pictures; Understand the characteristics of light and the equipment at hand, improvise and take the photos you want.

In the shooting environment, all available light sources (including natural light and artificial light) are called ambient light, such as candlelight, tungsten lamp, fluorescent light, neon light, fireplace, torch and fireworks. Except for the shed lights and flash lights controlled by photographers.

In space design and film shooting, ambient light is sometimes regarded as the main light source compared with auxiliary light; However, in plane photography, not only ambient light can be used as the main light source, but also other artificial light sources or light control devices (such as jumping lights or reflectors) can be used as auxiliary light sources. It is also quite common to use only ambient light when shooting in low main light.

Shooting with flash fill light can successfully highlight the theme and shoot a different feeling.

If the light in the scene is complex, a strong light source must be used as the main light, and the light ratio must be paid attention to to avoid the image performance problem caused by too strong contrast; In addition, how to strike a balance between the color temperature of the scene light source and the flash and successfully express the desired atmosphere is also a place that photographers must pay attention to.

Expand: Understand the contrast in photography.

For example, shooting such a scene with a wide snow surface, the skier slides in a black snow coat, and the sun shines on the snow surface behind him, which will produce a contrast negative.

On the contrary, a normal exposure film shoots a lighthouse, and the lighthouse is in a foggy environment, so this scene will produce a very flat and low contrast film, if this film is developed normally.

Comprehensive lighthouse photos. The second factor of comparison is exposure. If the film is overexposed, the contrast will decrease, even if the development is normal, the contrast will decrease. In order to understand how this happens, we should know the photosensitive characteristic curve of film in photography, that is, H-D curve. It is the basic tool of photography theory. This curve was extended by the names of two scientists: Haider and Dreyfield. This is a method to express photosensitivity developed in 1890. This curve is called the photosensitive curve. (This curve is also called D-I' OGE curve), which shows the relationship between the accumulation of silver and the exposure to a certain extent. It can be seen that the greater the exposure, the more silver will accumulate until it reaches a certain point.

At the toe of this curve, every increase in exposure only slightly increases the density. After reaching the shoulder, each increase in exposure will not increase the density proportionally. Only between the toes and shoulders, in the straight part of the curve, whenever the exposure increases a little, the density always increases proportionally.

What does this have to do with filming and developing? When the film is exposed, if it is overexposed, the highlight tone will move to the shoulder, while the middle tone is still in a straight line, resulting in a negative with a small contrast between the middle tone and the highlight tone, so overexposure will reduce the contrast.

contrast

On the other hand, if the film is underexposed, the tone of the highlight part will fall to the straight line of the characteristic curve, while the tone of the middle tone or shadow part will still be at the toe. In this way, the tone density of high light will increase faster than that of middle tone or shadow part, which will produce a negative with great contrast between high light tone and middle tone or shadow part, so it can be said that insufficient exposure can increase the contrast;

Because film can provide greater exposure latitude for overexposure, that is, it can provide greater exposure latitude than under exposure, so overexposure is better. If it is an ordinary scene, overexposure can have five or more exposure tolerances on most negative films without losing the details of highlights, but it cannot be underexposed. If an ordinary scene is exposed to two levels, the details of the shadow will be completely lost. When overexposed, the contrast will decrease unless the overexposure is serious.

Contrast and development, photosensitive characteristic curve, namely H-D curve, can show the relationship between density and exposure and development. Now let's see how development affects density and contrast. There are two main points:

Contrast and development

1. Increasing film development will increase the contrast;

2. Reduce contrast by reducing development.

How to increase or decrease the degree of development? Generally speaking, increasing development time will increase the degree of development. Another method is to increase the temperature of the developer, which can also improve the degree of development, because the higher the temperature, the greater the energy of the developer. The third way is to change to a developer with strong vitality.

To understand how development affects contrast, a simplified model can be used. Let's assume that there are ten layers of silver halide particles on the film irradiated by light. This is a simplified model. In reality, this is not the case, but there are many, I am afraid, thousands of layers thick and millions of layers thick in some places. Now suppose that one layer of silver halide particles appears every minute, five layers appear every five minutes, and 10 layer appears every minute.

How does development affect contrast?

At the end of the first minute, the first layer is developed, which includes each part of the light receiving area of the film. If development is stopped, the only contrast is due to the difference in silver accumulation between the part that has not been irradiated with light and the part that has been irradiated with any light. At the end of three minutes, two or three layers of silver shadows appeared in the least exposed part of the shadow, that is, the development exposure produced silver shadows with different thicknesses, but the part with strong highlights was far from being displayed, because it only reached the third layer, although it had been affected by the exposure to the tenth layer, but at this point of three minutes, there was only a small contrast on the negative.

Continue to develop for a longer time and increase the contrast between these regions, that is, some regions that are close to full development and some regions that are far from full development. Therefore, increasing development will increase contrast, and reducing development will also reduce contrast.

That is to say, the higher the degree of development, the greater the density difference, that is, the greater the contrast when the same exposure is increased. Sometimes you will see the word GAMMA with negative film mentioned in some technical classes. γ refers to the contrast on the negative film, specifically, it refers to the difference between the density of the thickest part and the density of the smallest and thinnest part on the negative film, which can be expressed by the inclination of the straight part of the photosensitive characteristic curve. Most negatives to be enlarged are developed to a gamma value equal to 6 or 70.