1 Color temperature adjustment
The color temperature selection of lamps is mostly in two ways. One is a color-changing temperature lamp type, which uses the brightness ratio of two groups of LED modules with low color and high color temperature to adjust the color temperature, and its advantage is that the color temperature is more accurate and easy to use. However, the disadvantage is that if the color temperature is adjusted to the highest or lowest, only half of the LED module of the lamp is in use, and the brightness is low. The other is the constant color temperature lamp type. Most are 3 200 K or 5 600 K.
However, due to the uneven technical level of manufacturers, the quality of LED modules is also different. The actual measurement index of color temperature and the nominal index often have a color difference of about 100 K ~ 150 K. In actual use, the accuracy of color temperature affects the matching of cameras, large screens and other equipment, which will directly affect the screen presentation. If the luminaire color temperature deviation is large, you can use Reiden color paper to solve. Assuming that the color temperature of the large screen is 5 800 K, and the color temperature of the lamp is 5 000 K, you only need to raise the color temperature to 5 800 K in front of the lamp on the Garredon 80 color paper to match the large screen. If the luminaire color temperature is higher than the large screen color temperature, use Reiden 85. It should be noted that any type of color paper has an impact on the color rendering index of the lamp. Therefore, in the selection of flat lamps, use the preliminary test to choose a relatively accurate LED flat lamp product.
2 Casting Angle
The best projection Angle of LED flat light as surface light is 40° ~ 45°. The height of many small studios in China is within 5 m, and depending on the situation, the projection Angle is often smaller. Generally speaking, the larger the projection Angle, the better the three-dimensional sense of the face light, the larger the face shadow area, the less stray light of the face light. The smaller the camera Angle, the stereoscopic sense of the face light becomes worse, the facial shadow area becomes smaller, and the stray light is easier to get on the background.
3 Lighting illumination
The standards of studio surface illumination are still not settled worldwide. News studios in Europe and the United States commonly use a low illumination of about 300 lx, with the camera's large aperture of 2.8 ~ 3.0, to obtain a larger background blur depth of field picture effect. CCTV news program surface illumination reaches 1 000 lx ~ 1 500 lx, camera aperture is about 5.6, the background is relatively clear picture effect. The advantage of high illumination is that the details of the character's skin and clothing are easier to show.
With the development of technology, the camera tolerance is improving, and the efficiency of the flat light is also improving. The two processing methods of high and low illumination are more based on the needs of subjective artistic effects. Using LED flat lamp lighting, the illuminance ratio of the face light and the backlight is usually 1:1.5, and the illuminance ratio of the face light and the background (large screen) is 3:1. The light ratio should also be adjusted according to the specific situation.
4 Shadow Processing
The host face shadow has always been the primary focus of lighting. The main ways to reduce shadows are:
(1) Increase the soft light sheet, the light quality becomes more soft;
(2) Use the mutual influence of multiple flat lights to dilute the shadow;
(3) Reduce the surface light projection Angle;
(4) Add eye lights to supplement the light on the host's eye bags, chin, and neck to dilute the shadow.
5 Light area control
Soft and uniform light quality is a major feature of LED flat lights. However, its light scattering is strong, and it is easy to produce more stray light projected to the background or other areas, resulting in problems such as the unclear level of the background bright picture. At present, there are several ways to control the light area of LED flat lights:
Use a shutter for shading. Due to the scattering light output characteristics of flat lamps, this shading effect is not very ideal.
It is a commonly used method to control the light area with a honeycomb front grid at different angles.
Use a black flag board or black cardboard to block out excess stray light.
Using black tin foil, cut the desired shape and fix it to the front of the light fixture.
