数码摄影之闪光灯应用技巧完全宝典(Digital photography flash applica

数码摄影之闪光灯应用技巧完全宝典（Digital photography flash application skills complete collection）
Foreword
Today, digital camera A new force suddenly rises. greatly change our way of photography, beyond imagination powerful enough to inspire each user shooting desire, as a game player, how to make full use of the advantages of digital camera, to enhance the quality of the photos? The author believes that the equipment itself is just one aspect, more important is the shooting skills, reasonable and correct use of optical and photographic knowledge mining equipment, their potential, while the digital camera is just one of the most easy to use, can not do the cost of test equipment. Photography techniques can be broad and profound, not in two words or three clear, this article from the flash point of view, especially for the digital camera, to explain the practice of digital photography, also hope to display slight skill before an expert, the right to do something!
Basics of flash technology
When it comes to flash, you may find it easy to use it at night. This is only part of it, in fact, the flash is an auxiliary tool use is very extensive, it is a photographic light source, when shooting, natural light environment (sunlight) or artificial light (light) is insufficient when the flash is made up of motor source of this problem. Despite the many kinds of types of flash, this paper refers to the single most common, various cameras have built-in flash one million times, it through the energy
storage capacitor and the coil, in an instant release and a pressure sensor, a pulse excited inert gas source, thereby obtaining the instantaneous power of strong.
Because the flash effect time is very short, generally speaking, the camera's shutter speed has been unable to adjust the flux effect, but for most digital cameras, the response speed of light without film, so don't even need to adjust the luminous flux, the light is not enough in the occasion, as long as the choice of the automatic entry into the flash mode or camera mode, then the shutter speed will automatically speed up to a relatively short value.
This usually does not matter, but when the ambient light is sufficient, a flash is accidentally enabled during close shooting, and overexposure occurs. On the other hand, if the ambient light is very dark, an excessive shutter speed will make the flash dark beyond the effective range.
To understand the characteristics of different reflective surface can better use the flash, because different objects have different reflection of light scattering ability, which is equivalent to a flash point light source, if the object is, or near the glass, marble, circuit board such as flat and smooth surface in the picture will be formed one of the highlights, the overall effect of failure. The way to avoid the glare is to change the lens angle, from side to side, so that the reflection of the flash is reflected from the other side without reflecting back.
Standard version of flash technology - built in flash
techniques
Reasonably set up and pay attention to checking the flash mode of digital camera
Various types of digital cameras generally have built-in flash, and many models can also external flash, therefore, there must be a flash mode of a digital camera, usually includes at least 3 basic modes: automatic, flash and no flash ", and number of camera plus 1-2 special modes" red eye, slow or all of, in the mode of operation is generally a button can control a few models with some menu selection mode, carefully check before use. In addition, the digital camera has a sleep mode, when from sleep wake up or shut down again after the boot, the flash mode may change, different models have different default mode, can not remember the last good state, some models will occur even after flash switch the "Browse / shooting" status the change of one of the problems most often make is to press the shutter after suddenly found the wrong way to flash again, so we must pay attention to check before shooting.
Need to consider the occasion of using flash
The following general occasions is to use flash, unless there is behind the "disabled" said that the scene in 1, otherwise don't hesitate no light or dim light when shooting objects lack of brightness, such as night night portrait
2 backlight, backlight shooting, shooting object and background luminance contrast time. For example, when the sun shines from behind the person, without a flash, the person will
be very dark.
3 when there are luminous objects and non luminous objects at the same time, for example, the TV screen, if you do not use flash, you can only see the screen picture, while the TV shell is black.
4 when the brightness of the object is uneven in different parts of the object, the brightness of the object can be uniform by using flash.
Do not use flash occasions
The following situations should normally be considered to turn off the flash
1 beyond the range of the flash and can not enter the effective range by adjusting the distance. During the day is generally not more than
2 meters, at night do not exceed
3 meters, to have good results, or else do not use the same, there will be no ideal results, some cameras flash more powerful exception, refer to its instructions bar.
2 in the dark place, if the subject is the background of large area lighting occasions, such as you go to the underwater world, through the tunnel when shooting underwater world, such as the color of the musical fountain, with a flash but when solved by pitch-dark, exposure compensation.
It doesn't work to use flash in such a wide range of fountains
No flash, increase the exposure time to achieve the desired effect
3 objects near, for example, within 15 cm or less, usually do not use flash, otherwise the brightness of the object surface is not uniform, and some parts may be overexposed.
4 when there is an obstacle between the flash and the object, for example, when the shot is near, the lens may completely block the light of the flash and lose its function.
To avoid possible flash, red eye: very simple, almost all of the cameras have red eye flash mode, note that the speed of time this mode will be extended, to hold the camera, or use three tripod.
Avoid exposure, uneven, or a big bright spot
When the object surface is light, flash light reflection will leave a big bright spot in the picture, undermine the overall effect, such as shot glass window objects, wrapped a layer of plastic film, and the objects in the film computer boards, will also have a strong reflection, it is best to remove film film, reflection can be far away from the object (the camera zoom lens to adjust the screen size), the most important thing is to transform the camera angle, side shooting, can make the spot reflection to the outside of the screen (Figure).
A large bright spot appears in the center of the circuit board
There's no point on the side
Use flash as auxiliary light source
The flash is not only used at night, but at any time, as long as the light and shade contrast of the different parts of the object is too large, the flash can be properly compensated by flash. (as in Fig.)
Without flash, the object is bright and black below
The use of flash assistance lighting, the whole is bright
Night portrait with a light background: correct use of slow sync flash mode
The use of flash, shutter speed will be accelerated, but if the background is pretty lights, it will seem so underexposed, now many digital cameras have slow sync flash mode in this mode, the shutter speed is not open because the flash becomes fast, light may flash two times, keep the shutter open during the,
First open the shutter or a period of time after the flash flash, or for a period of time, no matter what kind of treatment method, the principle is the same, namely the theme and background are the proper exposure light, attention should be paid to the exposure time, must hold the camera, or with three legs, and remind the subject to maintain posture don't move in the flash light before and bright after several seconds, otherwise the image due to move the hand shaking or object and virtual ghost. In addition, when a light background is dark, often need to increase the exposure compensation, because the subject is the
closer the flash under the action may be too bright, advised to properly reduce the flash intensity, prevent excessive exposure, reduce the strength of the concrete methods to flash back.
Using standard flash mode, the subject is bright and the background is not clear
Using slow sync flashes, both the subject and background are photographed
Pay attention to effective distance
General camera flash power is relatively weak, so the range is limited. When the day light, strong, backlighting film effective distance of only 1-2 meters, the night is long, but the digital camera flash range generally less than 3-5 meters.
An object with a phosphor screen
For example, monitors, televisions, etc., the screen is luminous, and the frame shell does not emit light, so you need to use a flash to shoot intact and bright. However, as the screen glass reflection, it is best to side to shoot (left and right, up and down angle can be), in order to avoid a big bright spot in the middle.
(compare to figure 3/4)
Without flash, the screen is bright and the frame is black
After use, all of them are clear
In addition, due to the screen refresh rate, and scan rate of digital camera will beat, causing a slow rolling dark, the solution is to reduce the shutter speed (such as slow sync mode), sometimes it repeated the experiment several times before they got satisfactory results (Figure)
Camera and monitor refresh frequency difference, beat to make rolling dark area
Reduce the shutter speed to get the normal picture
Use flash under water
Water absorption of light is relatively serious, so underwater photography of light is very poor, the scope of the flash underwater can only reach half of its effective distance, attention should be paid to avoid the problem of insufficient exposure. In addition, if you are shooting across the glass to the water body, the flash should be close to the glass wall, or light is reflected, but because the camera more often than the location of the flash is prominent, so in the actual operation is hard to realize, this is probably the only external flash in order to solve the problem, or simply without flash and by extension the exposure time to shoot.
How do you adjust the brightness of the flash?
The maximum brightness of the flash is generally determined by its own characteristics, it is impossible to increase, but to
reduce the intensity or can, method is to use gauze or transparent paper cover, generally a layer of gauze can be reduced to 50%, the 2 layer can be reduced to about 1/4. In actual combat, there is often no such condition to find gauze, then one of the easiest way is to directly block the flash with your fingers! Be careful not to block the center of the flash, but start from the edge to the center, with your fingers tight. This method is very effective.
Note that the lens is kept clean
When using flash at night, pay special attention to the cleanliness of the lens, which is believed to be unexpected by many friends. In front of the lens of digital cameras, there is usually a piece of protective glass. If there is dust on it, it may not affect much during the day, but when the flash is used at night, it will cause obvious spot. Beijing sandstorm big, I once in the evening shooting, suddenly found the picture has suspicious spots. (Figure 13) look carefully,
There is a lot of white dot in this picture.
Thought it was a light, and later realized that the possible lens is dirty, wipe clean and take it all normal, but a lot of photos but need to delete remake to spend extra time to clean the importance of visible camera.
Additional skills for flash - use of an external flash
Why use an external flash? The reason is because the flash camera position, built-in properties are fixed, not to provide
more features and flexible setup, such as the above mentioned, in order to avoid the central flash highlights, had to side angles, if must center position picture of how to do? What if the area of the object is too large to be even illuminated?... Only an external flash can give you more control.
In the current mainstream digital camera, and not all can be external synchronous flash, you must first understand your machine is supported, and what support interface, if has the ability of words, very lucky, you can use it skillfully to further improve the photography skill!
Use indirect flash
What is said above is direct flash, that is, the flash directly targets the object, while in many other cases it is more advantageous to use indirect flash. The so-called indirect flash flash exposure is to the ceiling or wall or umbrella, using their diffuse uniform irradiation target, this photo shoot, the light will be more gentle, even without a trace of flash! Only external flash lights can do this easily. In the use of indirect flash, on the one hand, the power of the flash should be strong enough, in addition, the ceiling or wall should be dominated by white, otherwise the effect will not be good!
Use special continuous flash to achieve special effects
If the flash supports a continuous burst of light, the B or T gates of the camera (not all digital cameras have these features) have some special effects. For example, a moving object can take a series of tracks. For larger scenes, flash can not even light
up when the camera with B T or, in one or more flash times from different angles by irradiation, the photo will be the overall brightness will be smooth and soft, and even flash caused even the shadow of it is very difficult to see. These two techniques are difficult and have some limitations.。