Lighting method of flash photography

There are several ways to eliminate flash lighting: in flash photography, the flash is placed on the camera and shot by direct front lighting. This lighting method is called direct flash lighting.

The characteristic of direct flash lighting is that it can quickly capture the instantaneous image of the subject in various environments, and it is the simplest and most convenient lighting method in flash photography. However, this kind of direct light from the front often makes the image appear dull and tasteless, and the three-dimensional sense is not obvious, and the level is not rich and the texture is not strong.

Taking portrait photos with direct light often produces the effect that people are bright and the background is dark. With the increase of flash distance, the contrast between people and background gradually weakens. When the distance is quite far, there is almost no difference between the brightness of the flash and the background. If you use wide-angle, standard and telescopic lenses to shoot portraits of people under the flash, it is required that the proportion of people shot by the three centralized lenses is roughly the same. Wide-angle lens needs to be shot at close range, and the effect of flash lighting is that the characters are bright and the background is dark; The standard lens needs mid-range shooting, and the effect of flash lighting is that the characters are bright and the background is dim; Telescopes need long-distance shooting, and the effect of flash lighting is that people are brighter and the background is gray. As far as the brightness of the background is concerned, due to the different flash distance, three effects can be formed: dark background, gray background and bright background. Of course, with the change of flash distance, the exposure should be adjusted appropriately. In flash photography, a layer of barrier with astigmatism is added in front of the flash placed on the camera, so that the light emitted by the flash passes through the barrier and becomes soft scattered light, illuminating the subject. This lighting method is called scattered flash lighting.

Dispersed flash lighting is one of the methods to avoid dazzling flash and strong contrast in flash photography. Its characteristic is that it can adjust the light and shade with soft light, ease the contrast, and depict all the characteristics of the subject with even illumination. In addition to the flash diffusion cover provided by some flashlights, handkerchiefs, white gauze or translucent tissue paper can also be used to block the diffusion flash. Some flashlights can take down the reflector, so that the light becomes scattered light that shines in all directions. This method is also an effective scattering flash lighting. In flash photography, it is very convenient to use white or light handkerchief as a scattering shielding tool, which can be single-layer shielding or multi-layer shielding. When a handkerchief is used to block the flash, the brightness of the flash will be weakened. The more layers are blocked, the darker the light is. In terms of photographic exposure, it is necessary to adapt to the change of light and ensure correct exposure. Then, how to choose the aperture coefficient when the handkerchief blocks the flash? There is such a data for reference: take a white or light handkerchief as an example, it takes about one aperture to cover each layer of handkerchief.

There are often two situations that may lead to the failure of shooting portraits directly from the front with a flash. First, there is obvious projection behind the subject, which weakens the performance of the main characters; Second, the distance between the subject and the background is compressed, and the environment and the background are so real that they feel like towels together. These two points are the limitations of direct flash lighting, and decentralized flash lighting can make up for these shortcomings appropriately. When the flash is blocked, the brightness of the light decreases, and when the circle is properly opened, the projection of the subject on the background will become blurred and diluted with a larger aperture, making it less obvious. Set off a clear portrait with a blurred and faded background, and there will be no feeling of sticking together.

In flash photography, the flash is aimed at light-colored walls, ceilings and other reflective objects, and becomes uniform and soft scattered light to illuminate the subject. This lighting method is called reflective flash lighting method, also known as indirect flash lighting method.

Backflash can produce soft light, which is similar to natural light when thin clouds cover the sun or cloudy days. Backflash lighting can make indoor light more uniform, and the brightness of the subject is not much different from the environmental background. Exposure control is easier to master, and there will be no direct light effect with bright foreground and dark background. For example, when shooting in a small room, the camera is very close to the person being photographed, so it is not suitable for direct flash lighting on the front. The flash flashes on the white wall at the upper left, and a large amount of scattered light is reflected from the wall and ceiling, so that the renovated room is generally and evenly illuminated, and people and the environment are brighter, which has a three-dimensional effect of lighting. This flashback can often produce two kinds of illumination light at the same time. First, the beam inverted by the inversion plane becomes the main light to shape the character image; Second, the backlight is backlit by the surrounding walls for the second time, which constitutes the auxiliary light for people and the environment.

Generally speaking, the reflective objects selected for flashback lighting should be bright white or light-colored objects with uniform reflection, and attention should be paid to avoid blocking mirrors, glass photo frames or bright electroplated objects hanging on the wall, as well as painting furniture. Because these objects will reverse the direction of the flash light and destroy the soft lighting effect. For color photography, a single white object must be selected as a reflector, so as to ensure that the photographed photos will not be distorted by the reflection of colored objects. If the shooting environment happens to be not white, but colorful walls and ceilings, you can temporarily hang white paper or sheets on the walls as reflectors, and you can get the lighting suitable for color films. If you want to create a special color effect, you can choose those colored objects as reflectors.

The exposure of reflected flash lighting is quite different from that of direct and scattered flash lighting, and the difference lies in the difference of flash lighting distance. The exposure of direct and scattered flash lighting is determined by the linear distance from the flash to the subject, and the actual distance of reflective flash lighting is the sum of two distances, namely, the distance from the flash to the reflector and the distance from the reflector to the subject. In addition, the reflectivity of reflective objects should be considered. Objects with high reflectivity reflect more light and have strong brightness. Objects with low reflectivity reflect less light and have weak brightness. For example, the reflectivity of white walls and ceilings is about 70%. When reflective flash lighting is used in this environment, the aperture coefficient required for exposure can be calculated by the following formula:

f=gn÷(l 1+l2)×70%

Namely: aperture = flash index ÷ (distance from flash to reflector+distance from reflector to subject) × reflectivity.

Reflective umbrella is a special reflective tool with different colors. The silver umbrella does not change the color temperature of the flash; The golden umbrella can appropriately reduce the color temperature of the flash; The blue umbrella surface can appropriately improve the color temperature of the flash. In flash photography, the most commonly used reflective umbrellas are mostly white or silver. When using the reflective umbrella, you can move the position of the flashlight on the umbrella handle to change the irradiation area and light brightness. In the aspect of exposure control, we should first get the exposure standard of reflective umbrella through experiments. Then according to the distance from the reflective umbrella to the subject, the aperture coefficient required for exposure is calculated.

When taking portraits at close range, if there is nothing around to be used as a reflector, the photographer can also aim the flash at his chest and flash at an appropriate angle. Through the reflection of light-colored clothes, the brightness can be reduced, and the photographed person can be illuminated with soft scattered light. When using the flash as the main lighting, please separate the flash from the camera and connect it with a long connecting cable to illuminate the subject from the front. This kind of lighting is called side flash lighting.

The method of side flash lighting can produce side projection and form obvious contrast between light and shade, which is beneficial to the expression of three-dimensional sense and space sense. This lighting method can appropriately improve the flat and lifeless light effect produced by single-lamp front flash lighting. The photos taken by the front flash are gray in tone, dull in light and lack of three-dimensional sense; The photos taken by side flash lighting have bright colors, vivid light and strong three-dimensional sense.

When shooting multiple vertically arranged objects, the color front flashes, and the heat must be brighter as it gets closer, and the darker it gets, the smaller the lighting concentration; If we switch to side flash lighting, the illumination brightness of objects with different distances before and after can be basically uniform, and the illumination depth can be increased.

The method of using side flash lighting is best combined with the method of reverse flash lighting. For example, in an indoor shooting environment, the flash placed on one side of the camera is slightly lifted upward, so that the flash can not only directly shoot the subject, but also partially scatter the light from the ceiling to supplement the illumination of the shadow part of the subject, which can alleviate the contrast between light and dark on the side light, enrich the tone levels, and help strengthen the expression of three-dimensional sense and space sense. In order to create an ideal lighting effect, in flash photography, multiple flashes can be used to illuminate the subject at the same time. This lighting method is called multi-lamp flash lighting method.

The method of multi-lamp flashing lighting is to use two or more flashlights as main lights and auxiliary lights respectively at the same time. The main light is used to shape the basic form of the subject and express its characteristics; Auxiliary light is used to supplement the brightness of the shadow formed by the main light, reduce the contrast between light and dark, and enrich the tone level.

In publicity photography such as news photography, if flash lighting is needed, as long as the shooting site conditions permit, single-lamp lighting should be avoided as much as possible during the day, and double-lamp or multi-lamp lighting should be used. At present, many professional photographers usually have two or three flashlights to create special lighting effects in some cases. For example, the drilling workers in Daqing Oilfield happily called their superiors. The shooting environment is in a wooden shed with doors and windows facing north on the drilling front line, and the light is dim. This dim lighting effect is not consistent with a happy mood. Therefore, imagine a bright beam of sunshine shining into the room from the window, forming a sunshine effect on the oil workers' faces to strengthen the festive atmosphere, and choose the well platform far away from the window as the background to set off the typical environment of the characters. When lighting, connect a flash lamp to the synchronizer and hide it outside the upper right corner of the window, aiming at the workers in the window at an appropriate angle; The other flash is installed on the camera and wrapped in two handkerchiefs to reduce the brightness and serve as an auxiliary lighting for the shadow part. Because sub-light, like sunshine, enters the room through the window, which has formed a light effect of alternating light and dark on the characters, and the joyful atmosphere of oil workers has been overflowed and strengthened.

In addition to the above methods, multi-lamp flash lighting can also open the shutter (door B or door T) in a dark environment (such as night photography), and use one or two lamps for multi-lamp flash at different angles and distances, so that all parts of the scene can be properly illuminated. Its effect is similar to multi-lamp synchronous flash, which is especially suitable for shooting still big scenes.

The exposure of multi-lamp flash lighting should be determined according to the lighting angle, distance and luminous intensity of additional flash. If two flashlights illuminate the same object at the same distance, and the included angle between the two lamps does not exceed 30, then the aperture can be reduced by one level compared with the exposure standard of one lamp; If the angle of the two beams is between 40 and 80, reduce the aperture by half a step.

When adding an auxiliary lamp, it is not necessary to consider the brightness of the auxiliary lamp, but only to determine the exposure according to the brightness and distance of the main lamp. These situations are as follows: the angle between the main lamp and the auxiliary lamp exceeds 80; Additional sub-light sources are used for contour lighting behind the main body; The degree of the auxiliary lamp is only half that of the main lamp; The distance between the auxiliary lamp and the subject is one and a half times farther than that of the main lamp; An independent lamp used for scattered light or reflected light illumination.

In photography, many photographers have accumulated and created many effective shining lighting methods. Limited to space, it is impossible to illustrate them one by one. The basic methods introduced here are for your reference only. I hope I can draw inferences from others, explore extensively and create more experiences. When shooting in sunlight, overhead light and backlight, the flash can be used as auxiliary light to reduce the light ratio. This is especially suitable for portrait photography, which can not only improve the lighting effect, but also help to express the vivid and natural facial expressions of the characters.

The amount of auxiliary light should be appropriate, and all shadows should not be knocked out, otherwise it will be unnatural. The distance data provided in the attached table 1 is based on the light ratio of 3: 1. To reduce the light ratio to 2: 1, just reduce the distance in the table by one third. If you want to rise to 5: 1, you only need to increase the distance by one third. Attached Table 2 lists various exposure value of auxiliary flash. Auxiliary flash, like forward flash, mainly depends on film sensitivity, shutter speed and aperture value. Under the condition of constant exposure, changing different combinations of speed and aperture can make you change the distance from the subject while maintaining the same light ratio. In the table, the reference exposure of smooth light is based on the reciprocal of film sensitivity and shutter speed, and the aperture is f/ 16. Since the maximum synchronization speed of most focal plane shutters and electronic flashlights is 1/60 seconds (some can reach 1/250 seconds), it can be seen from the table that the distance range that can be successfully used as auxiliary flashlights is limited. If the blade shutter uses a high-light electronic flash, the effective distance above it will be much larger.

Determine the exposure of the auxiliary flash.

First method

1. Use the exposure meter to measure the correct exposure of the object in the sun, and choose the shutter speed that can be synchronized with the flash (for example, the focal plane shutter is usually below 1/60s). According to this speed, find the aperture value from the exposure meter.

2. Find the flash index from the flash or film instructions.

3. The flash index divided by the aperture value is the distance between the flash and the subject at the light ratio of 2: 1.

4. If you want to change the light ratio, you can convert the above distances as follows: distance X 1.5= light ratio distance 3: 1, distance x 2.0- light ratio distance 5: 1. The light ratio of color film should be 2: 1 or 3:1; Black and white film is 3: 1 to 5: 1.

The second method

1. Divide the flash index by the distance from the flash to the subject to get the required aperture value.

2. Reduce the aperture by one step, and the light ratio is 3:1; Take the second gear, and the light ratio is 5: 1.

3. Use the exposure meter to measure the exposure value in the sunlight at that time, and then find out the required shutter speed according to the selected aperture. If the speed can be synchronized with the flash, press this button. If not, properly change the distance between the lamp and the main body to obtain the required aperture and speed. When shooting indoors with a flash, the brightness of the flash often exceeds the brightness of the scene light, exposing the traces of artificial light, which is not conducive to the real atmosphere of the photo. In order to avoid this phenomenon, we can choose a lower shutter speed and add a medium gray filter in front of the flash (not in front of the lens) to reduce the light intensity. When the light intensity decreases, a larger aperture can be used. A larger aperture and a lower shutter speed can give the spotlight more time to illuminate the photosensitive film. So as to make the photos look more natural.