What does the camera need the green screen button for?

Button image background: green/blue keying mode: hardware keying/software keying (chroma keying program)

Green screen: the color purity should be high, clean and flat without wrinkles. The range of the subject determines the size of the illuminated green screen.

Lighting: The large-area light source hits the green screen more evenly, while avoiding the excessive brightness of the green screen and preventing the green from "overflowing". At around 40 (the "pseudo color" function of the monitor can check the brightness of the picture), the brightness difference between the green screen and the characters is opened by the lights in different areas. The face light of the character should match the background light replaced by the green screen key to enhance the realism of the picture.

Green screen ordinary light bitmap

Full-screen shooting is when the whole person needs to appear on the set. If you need to walk, you need a lamp to illuminate the floor. Or contact with the back wall, the lighting method is very different. In order to get the shadow, it is necessary to ensure that there is enough light on the subject to cast the shadow, and at the same time, it is necessary to ensure that there is enough light on the green screen without too much green overflowing to the actors. At the same time, it is necessary to fill the light from the side to illuminate the actors to prevent green overflow.

Actor: The actor is far enough away from the green screen. If there is enough space and they are at least 6 feet (1 foot =0.3048 meters), don't wear clothes with the same color and green reflection as the button curtain. Prevent that green color from overflowing, and at the same time prevent the actor from entering the light range that illuminates the green screen.

White balance: gray card dialogue.

Aperture: The aperture of the camera should be as large as possible, but make sure that the hair is in focus and the green screen is in Jiao Wai. The larger the aperture, the shallower the depth of field, and it is easier for green or blue screens to buckle out the background.

Shutter: Setting a higher shutter can reduce smear caused by motion blur, while a lower shutter speed will lead to green smear, which will affect the keying effect.

Motion position: In order to shoot a shocking scene, we must consider adding a tracking point on the green screen with a hand-held motion camera. When the camera is shooting in motion, the background of the picture will also move and shift. The colors of green screen and blue screen are monotonous and consistent, and lack of depth relationship, which often cannot provide accurate camera motion information for later synthesis. Therefore, it is necessary to add some marks on the screen. By tracking these key points, post-producers can find the information of the camera, thus adjusting the movement relationship between the protagonist and the background. Setting the tracking point is generally to stick some equidistant or equal lines or points on the green screen and the blue screen. If it is detailed enough, these marks can be made different.

Restore authenticity: shoot the angle and texture of ambient light on the spot, so as to illuminate the people in front of the green back, record the focal length and aperture of the lens used in background shooting, record the horizontal height of the camera at that time and set the camera angle, so as to set the plane position.