When buying a projector, many users are confused about whether to buy a short focal length or a long focal length. When you buy a projector, you may only focus on the brightness, resolution and other values, but you may not know that the throw ratio is also an important indicator for evaluating a projector. Even in daily use, the throw ratio is important for users. The significance is greater than indicators such as brightness.
What is throw ratio
The projection ratio is actually the ratio of the projection distance to the screen width. The smaller the ratio, the shorter the projection distance required to project the same screen width. For example, if the throw ratio of a projector is 1, then using this projector to project a 100-inch screen requires the lens to be 2.214 meters away from the screen.
The throw ratio is the ratio of the projection distance/screen width
Regarding the standard of throw ratio, it is generally considered that when the throw ratio is less than 1, it is called a short-throw lens; when the throw ratio reaches below 0.6, we usually call it an ultra-short throw lens;
The difference between short focus projection and long focus projection
The main difference between them is the distance required to project the same size image.
The distance required for a telephoto projector to project a 100-inch screen size is more than 6 feet (about 1.9 meters), and it needs a large enough space to be able to use it.
The distance required for a short throw projector to project a 100-inch screen size is about 4.5 feet (about 1.3), which is more suitable for use in meeting rooms or classrooms.
Ultra-short throw projector, the distance required to project a 100-inch screen is about 15-20 inches (about 0.5 meters), suitable for use in small places such as rooms.
Therefore, when choosing a telephoto or short-focus projection, it mainly depends on the space used. If the projection space is large enough, you can safely choose long-focus projection, but if the space is relatively small, you should choose short-focus or ultra-short-focus projection as much as possible. In general, short-focus projection may be more adaptable.