Color temperature-Know the white balance of the camera.

About color temperature-understanding the white balance of the camera

Sometimes we will encounter photos with wrong colors, such as yellow and blue, because the camera has a problem in detecting the color temperature. The so-called color temperature is literally the color? Temperature? Therefore, there is a difference between cold and warm. Intuitively, the warm color is red and yellow, and the cool color is cyan, and the unit is Kelvin (K). If the camera setting option is turned on, there is an option to adjust the color temperature in the white balance (WB). Then you may ask, why put the color temperature in a name called? White balance? Why not just call it color temperature? This is because there is a color concept behind it.

What is warmth? What is cold?

In daily life, we will encounter different types of light, such as sunlight, light, tube light, candle light and other common color temperature values in photography, usually at 2000K? 10000K with 5000? 5600K is a neutral color temperature point, such as the noon sun. Warm color is low color temperature, and red light is more common, such as candlelight and lamp bile light, around 2000? About 3000K; The cooler colors are high color temperature and blue light, about 7000K or more, such as the light in the cloudy world. Different color temperatures produced by different light sources will affect the color performance of the illuminated object.

The situation of fireworks is special, because its light source is constantly changing, but its color temperature is warmer, so more consideration should be given.

The color tone of the background building is primitive, so it is recommended to use the color temperature value between 3000 -5000k when setting.

White balance-find the white of the photo.

The human eye has a high sensitivity to color discrimination, and can distinguish white objects in most cases. However, the photosensitive element of the camera is not as good as the human eye. If it deviates too far from the neutral color temperature, it can't be corrected in sensing, which will cause color cast of the photo. The most common thing is that when the color temperature is much lower than the normal color temperature, the color tone will be yellow, especially the skin color of people will be particularly ugly, so it is necessary to change the color that is too warm. Cooling? Neutralization makes the hair color of the object in the stage behave as normal as in the sun. The basic principle of calibration is to make what was originally white still see white at different color temperatures, so what is it? White balance? . Then why not? Black Balance Because black behaves the same at any color temperature, it is impossible to correct the color temperature according to black.

In the film era, the preset color temperature of the film is usually used in the sun, about 5500-5600 K. If there is any deviation from the color temperature, a color filter should be added to correct the color, that is, a cold filter should be used in case of warm color, and a warm filter should be used in case of cold color. However, in the digital age, the photosensitive element has the function of color temperature correction, and the color temperature range can be adjusted according to the occasion.

This is the effect of automatic white balance (AWB) under indoor warm color lamps (left). If AWB can't restore the main body.

Color, and the camera supports RAW, you can change the color temperature value in RAW and then correct it (right).

General digital cameras have automatic, daylight, Miyun, tungsten lamp, lamp, flash and manual modes. However, the performance of each camera is different. If the camera is limited by design, for example, the detection range of automatic white balance is about 4000-7000K, there is nothing to be done when it deviates from the exaggerated environment of neutral color temperature. If necessary, you need to narrow the range with the preset color temperature or use manual white balance.

The following is a picture of Panasonic camera manually inputting color temperature (K). You can see that the color temperature table on the left hand side has options such as candles, lamps, sunshine, cloudy days and shadows from bottom to top, with values ranging from 2500? 10000K. The indoor light is a fluorescent tube, which is similar to the color temperature of the fluorescent tube when the value is 5400K. You can see that the background is white.

After seeing this input color temperature, perhaps everyone began to understand that the performance of the camera to different color temperatures is a relative adjustment. If the scene color temperature is higher or lower than the color temperature set by the camera, the color will appear relatively cold or warm. When the color temperature matches the color temperature set by the camera, the color can become normal.

List of color temperature related tools

Selection (1): white paper or 18% grey card.

If you want a more accurate color temperature, you can use the preset WB. The process is not complicated. As long as you take a picture of white paper or 18% gray card under the light source according to the camera program, the color temperature can be close to the value of the light source. However, it should be noted that if you use A4 paper that you carry with you, the color of the paper is not necessarily pure white, but mostly light blue, and the obtained color temperature may be biased. It is recommended to use a gray card with a medium tone to avoid color cast. Grey cards are especially suitable for commodity photography, which can keep the tone uniform. Generally, a high-quality gray card costs about HK$ 200. After use, it should be properly protected from light and moisture, because it may change color. If high color temperature accuracy is required, it is recommended to replace it once a year.

/kloc-one of 0/8% grey cards.

Option (2): spyder cube and Spyder Checkr.

There are actually many tools to choose from. For example, SpyderCube has three colors, namely white, 18% gray and black, which can measure the color performance of highlights, midtones and shadows under different light sources. When using it, put the Spyder cube in the scene, shoot it with RAW, and use automatic white balance. After that, as long as the white part is selected when adjusting the color temperature of RAW, the correct color can be restored at this color temperature. After that, as long as the color temperature value of RAW is input to other pictures with the same light source, the consistency of each picture can be guaranteed, which is very convenient for not having to adjust every picture once in the later stage.

Data color Spyder cube

Another tool with similar functions is Spyder Checkr, which is used in a similar way. The main difference is that Spyder Checkr can further compare other colors and adjust the color deviation of the camera more accurately. After adjustment, you can output a record file (template or Profile), and you can use it by inputting RAW pictures in the future.

Data color Spyder checker

Option (3): Expo CD

Another method is to measure the color temperature in advance, and the simplest one is expodisc. This product is only placed in front of the camera when setting the hand-white balance. expodisc？ ? The mirror will scatter the light source and turn it into a gray card. The biggest advantage of Expodisc is that after adjustment, the effect can be seen in real time when shooting on the spot, and it can cope with more complex light sources, especially indoor light. After adjusting the white balance, it can save a lot of problems in later estimation and adjustment, saving a lot of time. Compared with Spyder Cube, expodisc emphasizes the efficiency of real-time correction and reduces the later period, while Spyder Cube emphasizes consistency.

Exponential disk

Secret recipe (1): How to adjust the white balance of the flash?

Cameras usually have a preset flash white balance, but this only applies when the built-in flash is used as all light sources. However, in the case of shooting with flash, the subject is often influenced by flash and ambient light at the same time, which becomes a complicated situation of mixed light source. The slower the camera shutter, the higher the brightness setting and the heavier the live light ratio. Therefore, instead of using a fixed flash color temperature, it is better to use automatic white balance and RAW to double insurance.

Secret recipe (2): Is it useful if the color temperature is wrong?

When you know the correct color temperature, it's time to play with the color temperature. Sometimes it is not necessary to see white in every picture. For example, everyone likes the warm color expressed by candlelight, but it has no taste after correction, so knowing what you want will naturally know when to adjust the color temperature. For example, if you want to shoot a sunny evening, or if you want to shoot a Japanese blue-and-white cool tone, review the method of inputting color temperature above and you will know how to use color temperature to create an effect.

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