SLR flash

The English scientific name of flashlight is flashlight. Flash is also one of the ways to enhance exposure, especially in dim places, which helps to make the scenery brighter. There are also disadvantages to using flash. For example, when shooting people, the light of the flash may remain in the pupil of the eye, and then "red eye" will appear. Therefore, many camera manufacturers have added the function of "eliminating red eye" in their designs. Before turning on the flash, they will emit weak light to adapt to the pupil, and then make a real flash to avoid red eye. Generally, there are three flash modes for middle and low-grade digital cameras, namely, automatic flash, red eye removal and off flash. More advanced products also provide "forced flash" or even "slow flash" function.

Automatic Flash Usually, the flash mode of traditional film cameras and digital cameras is preset as "automatic flash" mode without any setting changes. At this point, the camera will automatically determine whether the light of the shooting scene is sufficient. If it is insufficient, it will automatically turn on the flash when shooting to make up for the lack of light. In most of our shooting situations, the "auto flash" mode is enough.

The English name of red eye prevention is Redeye reduction, and the sign on a digital camera is generally an "eye". When taking portrait photos (especially in close range and dark environment), the phenomenon of "red eye" often appears. This is caused by the flash reflected from the retina of the eye. If you don't want people's or animals' eyes to have "red eye", you can use the "red eye elimination" mode of the digital camera, and let the flash flash once or several times before the main flash and shooting to adapt to people's pupils. The following are different pictures taken in red-eye prevention mode and red-eye prevention mode.

Forcing not to flash will force the digital camera to turn off the flash. No matter what the lighting conditions of the shooting environment are, no flash is allowed. This function is most suitable for shooting in places where flash is forbidden.

Forced flash: whether in bright or low light environment, you can flash when you turn on the flash. Usually used to shoot people with their backs to the light source can enhance people's brightness, but it is easy to cause noise increase and overexposure.

Turn on the flash slowly and synchronously, which can flash in bright or low light environment. Usually used to shoot people with their backs to the light source can enhance people's brightness, but it is easy to cause noise increase and overexposure. When taking pictures in dim light, if you use a flash and a high shutter speed, it is easy to cause the foreground subject to be too bright or even dazzling, while the background is still gloomy and it is impossible to distinguish the details. "Slow flash synchronization" will delay the release speed of digital camera shutter, use flash to illuminate the foreground, and cooperate with slow shutter (such as 1/5 seconds) to expose the weak light background. In this way, you can take photos with harmonious exposure before and after.

In the case of weak light, the shutter speed of the front/Hou Lian synchronous flash is relatively slow, while the front/Hou Lian synchronous flash will hardly increase the shutter speed. For example, in normal metering, when the aperture is maximum, the shutter speed is 1 sec. After the first three flash modes are turned on, the shutter speed can be increased to 1/90 seconds. The front curtain flashes synchronously, flashing 1/90 seconds when the shutter is opened, and then continuing exposure to 1 second or 1/2 seconds. The Hou Lian synchronous flash is the opposite of the front curtain synchronous flash. After the shutter is opened, it doesn't start flashing until the shutter is closed.

The distance between flashlights is the effective lighting range of flashlights, usually in meters. For a flash, the product of distance and aperture is equal to the flash index. At present, the effective distance of flash of consumer digital camera is about 0.5-5 meters, and the effective distance of flash in different modes is slightly different. For example, in the case of micro-shooting, the distance of the flash can be within 1 meter.

Please pay attention to the distance between the camera and the subject when using the built-in flash. Too close will lead to overexposure, too far will make the light distribution uneven, leading to underexposure. Users had better consult the user manual of digital camera to know the use range of built-in flash, which can generally achieve good results. Using digital camera for macro shooting, because it is very close to the subject, using the built-in flash will only lead to overexposure, so it is necessary to reduce the light.

Dimming is to reduce the output intensity of the flash. You can adjust it in a digital camera, but it's not enough. The light is still strong. You can cover the flash with your hands and pay attention to your fingers, which can reduce the light intensity to some extent. In practical use, it is found that simply using soft paper such as napkins can also have a good effect and make the light soft. Dimming will also reduce the effective distance of the flash.

Generally speaking, it is not suitable to use flash when shooting at night, especially when shooting distant scenes, because the distance is too far, and the flash doesn't work at all. Small aperture and long exposure can show beautiful night scenes. Flash is generally used to shoot portraits at night. If you directly turn on the flash to take a portrait, the restoration of the character is normal, but the night scene behind it is very dark and cannot be restored. At this time, you need to use the slow flash function. Slow flash will take a long shutter time, illuminate the subject with a flash, and cooperate with the slow shutter to ensure that the background can also be displayed. If your camera already has a slow flash function, just use it directly. Otherwise, you can set a longer exposure time in manual mode and achieve the same effect.

How to choose a flash Since the advent of a large number of small electronic flash lamps, it has become an artificial light source widely used by amateur photographers because of its portability, low price and sufficient luminous intensity, which has brought great convenience to all kinds of photography. However, due to the wide variety of flashlights on the market, the efficiency is also very different, so some considerations should be made when matching them.

First consider the index of the flash. Index is the performance index of the flash, which indicates the luminous energy of the flash. The bigger the index, the stronger the flash. In order to adapt to a variety of shooting environments, it is best to choose a larger index. Of course, the larger the index, the higher the volume, power consumption and price of the flash, but this will not bring too much burden to the photographer, and it is worthwhile compared with its function.

Secondly, it depends on its performance. There are two kinds of flash: special flash can be controlled by camera computer as long as it is plugged in, and the synchronous shutter can be automatically selected within a certain range, and the flash intensity can be adjusted for different exposures; Generally, it is necessary to adjust the aperture according to the table on the lamp and different shooting distances in order to expose correctly. Special flash can only be used for TTL photometry cameras. Just look at the' hot boots' on the camera flash socket. If there are multiple contacts on it, this kind of camera can be used together. It is best to choose this kind of flash. For cameras with only one contact or only one flash socket, only ordinary cameras can be used. Of course, there are also two kinds of general manual and automatic, which can be selected according to needs.

How to use the flash correctly outdoors? Strong sunlight can produce annoying dark facial shadows in photos. You can use a flash to illuminate your face and eliminate shadows.

Turn on the flash when taking pictures of people on sunny days. You can choose to use full flash mode or full flash mode. You can use all-flash mode if the character is within five feet, and you need all-flash mode if it is outside five feet. When using a digital camera, observe the effect through the photo display panel.

On cloudy days, you can use this mode if the camera has enough flash mode. A flash can illuminate a person's face and make it stand out. You can also take pictures without flash, sometimes soft light in dark weather will produce pleasant effects.

How to use wide-angle lens and flash to avoid dark corners? In the design of flash lamp, reflector is a key factor in order to obtain a good flash range. It is very difficult to make a flash that can be used for 24 mm, 2 1 mm or 18 mm wide-angle lenses. The wider the field of vision, the more difficult it is. The main problem is that the flash range should be wide and the light in the whole range should be very uniform.

Most portable small flashlights have the same flash range as a 35 mm lens. However, when this flash is used for a 28 mm lens, the flash range and uniformity become insufficient. Most advanced flashlights are equipped with wide-angle diffuser, which can expand the flash range of flashlights and make them have the same field of vision as 28 mm lenses, and some can even be used for 24 mm lenses. However, for a 2 1mm super wide-angle lens or a lens with a shorter focal length, the diffuser is powerless. This problem is particularly obvious when taking group photos or indoor interiors. The solution is to use a reflective flash.

The walls and ceilings around the room can reflect the flash, and some types of reflectors can also achieve this goal. Lighting can turn the flash, making it easier for you to reflect the flash. The exposure of reflected flash will increase with the distance between the flash and the object. Accurate exposure can be measured by using flash exposure meter.

In flash photography; The most important problem is to find out the distance from the flash to the object, not the distance from the camera to the object. When shooting crowds and groups, if the pictures can fit together, it is best to use a 35 mm lens and shoot at a distance of 10 feet. If you change to a 24 mm lens, the flash can't illuminate the whole crowd. At this time, a reflective flash will be used. In ordinary families, the ceiling is used to reflect the flash, and the distance between the flash and the object is about twice.

At this time, the exposure should be four times the original, that is, two steps should be added. Obviously, the exposure will change with the height of the ceiling. The average height of the ceiling of a modern house is about 9 feet, so we can use multi-level exposure (that is, increase one file, shoot one file, decrease one file and shoot another file). The experience gained in this way has a revised benchmark in future photography, no matter whether the ceiling is high or low. Take photos under a 9-foot-high white ceiling, put the flash on the camera socket, raise it to eye level to reflect the flash, and increase the exposure level by 2. This is the data measured by the flash exposure instrument at a distance of 0/2 feet from the camera/kloc-.

Another problem you will encounter when taking pictures is the color of the reflective surface. If black and white film is used, there is no problem. However, if color film is used and the reflective surface is pink, the photo or slide will be dyed pink. Pay more attention to the color of the reflective surface, which may hinder you from using the reflective flash.

The new flash has a reflector, which can be attached to the reflector of the flash. In this way, a very uniform reflected light level can be obtained. Sometimes, if a wide-angle diffuser is added to the flash head, the flash range can meet the requirements of a millimeter wide-angle mirror.

The latest product is a flash with a zoom head. There is a control button on the flash head to change the flash range of the flash. Some flashlights have a zoom range of 20 to 200mm. But this kind of direct flash is stronger. If the zoom flash is most suitable for taking group photos, then the flash with reflector is more suitable for taking indoor scenes because of its soft light.

In addition to flash accessories, ceilings and walls, another way to reflect flash is to use portable small reflective screens to diffuse and soften light. Although the reflective umbrella is more directional than the reflector, it is also beneficial to wide-angle photography.

If you often take wide-angle photos, you can consider multi-lamp flash. Using two medium-sized flash lamps will have more control space than using one high-power flash lamp, and the effect is very good. If you add a reflector or umbrella to both flashlights, the flash range will be much larger. You can connect two flashlights with a wire with several plugs and plug them into the synchronous jack of the camera. A more advanced method is to equip both flashlights with "induction" devices, and use the low-power flashlight on the camera to make them flash at the same time, so that the connection can be omitted and there will be no entanglement everywhere.

If you want to shoot the dark night scene inside or outside a building, you can "draw" it with a flash, which is another very useful technology. Use low-speed film when taking pictures; The camera is supported on a tripod, and the picture is determined by the viewfinder. There is no flash on the camera, so you should be close to the object and flash more so that the object can be properly illuminated, just like painting on the object with a flash. The aperture should be determined based on the distance from the flash to the object, not the distance from the camera to the object. Before shooting, take a closer look at the light shining on the object. Balance the well-lit part with the dark part illuminated by the flash. Because it is difficult to estimate the exposure, multi-level exposure can be adopted by changing the opening time of the shutter and the number of flashes of the flash. Exposure parameters should be recorded in detail for future reference. The modern film exposure latitude is very tall. As long as you shoot carefully, you can get satisfactory results.