The Universal Formula Helps You Calculate The Optimal Projection Distance of the Projector

When we purchase the projector, the first thing we noticed that the projector brightness, contrast, uniformity, resolution, and other important parameters, in addition, we also want to figure out the projector focal length and Projector LCD size and other parameters, in order to be suitable for our use in the projection distance and Projector LCD size.

The projection distance and Projector LCD size is closely related to the projector focal length and picture size, their mutual relationship is as follows:

Given the size of the picture, the projection distance is obtained: 

Minimum projection distance (m) = minimum focal length (m) x picture size (in) ÷ Projector LCD size (in) 

Maximum projection distance (m) = maximum focal length (m) x picture size (in) ÷ Projector LCD size (in) 

Given the projection distance to obtain the picture size: 

Maximum projection screen (m) = projection distance (m) x Projector LCD size (inches) ÷ minimum focal length (m) 

Minimum projection screen (m) = projection distance (m) x screen size (inches) ÷ maximum focal length (m) 

For Example ：

1、The focal distance of Toshiba TLP-S71 is 26.5mm~31.5mm, Projector LCD size is 0.7 inch which need 85” picture

Minimum projection distance (m) =0.0265 m x 85 in ÷0.7 in = 3.217 m 

Maximum projection distance (m) =0.0315 m x 85 in ÷0.7 in = 3.825 m 

2、Known: EPSON EMP-6000 focal length is 24.0-38.2 mm, Projector LCD size is 0.8 inch, projection distance is 4 meters, seeking: the largest projection screen and the smallest projection screen. 

Maximum projection screen (in) =4 m x 0.8 in ÷0.024 m = 133.3 in 

Minimum projection screen (in) =4 m x 0.8 in ÷0.0382 m = 83 in 

As mentioned above, we need to select the projection Projector LCD size according to the projection picture size. The Projector LCD size we are talking about is actually the diagonal length of the screen, in inches.  In general, China's ruler scale is meters, measure the length and width are more convenient, so it is necessary to know the screen width (meters) and screen height (meters) according to the Projector LCD size (inches)