The proper projection screen size is determined by the viewing distance

In real life, some things have scientific basis and laws to follow. If there is no better solution, one of the reasons is the lack of individual knowledge. For example: the appropriate projection screen size is determined by the viewing distance. Do you apply it in real life?

There is a certain relationship between the size of the projection screen and the viewing distance, because other factors or parameters can be further considered only if the viewing position and the position of the projection screen are determined first. The viewing angle can be converted into the relationship between the viewing distance and the width of the projection screen through mathematical calculation. Assuming that the ratio of the viewing distance to the width of the screen is A, and the viewing angle is α, the relationship between the two is Au003d1/2tgα /2. Because they are professional, they are trusted. The two world-renowned audio and video agencies, THX and ISF, have corresponding recommendations on the relationship between viewing distance and projection screen size. THX recommends a minimum viewing angle of 28° when watching 16:9 HD programs, an ideal viewing angle of 40°, and a 52° viewing angle when watching 2.35:1 HD movies. The ISF recommends that viewers with 20/20 visual acuity (excellent vision) have a viewing angle of 33° when watching 16:9 high-definition programs and 25° when watching standard-definition programs. In other words, THX recommends an ideal A of 1.37 when watching a 16:9 HD program, and an ideal A of 1.03 when watching a 2.35:1 HD movie. And ISF is 2.26 when watching 4:3 standard definition programs, ideally, A is 1.69 when watching 16:9 high-definition programs.