The relationship between the width of the projected image and the throw distance determines the throw ratio specification. Throw distance is the space between the lens of the projector and the projected image.
Knowing a projector's throw ratio helps consumers and professionals determine what image size can be projected from a certain distance away. For example, if a projector has a listed throw ratio of 1.2:1, and the screen is ten feet (10 ft.) wide. Take the screen's width and multiply it by the first number in the throw ratio. This formula is screen width x throw ratio = throw distance. For the example above, a 10 ft screen width x 1.2, the first number in the throw ratio = 12 ft, is how far away the projector should be from the screen.
It is imperative to consider where you wish to position your projector and the size of the image or screen you intend to project onto.
The throw ratio is the relation between the throw distance (the distance between the projector's lens and the projected image) and the width of the projected image. Understanding how to calculate the throw ratio equation can be handy when shopping for the best projector for your home theater space.
If you are not interested in doing the math, don’t worry. Almost all manufacturers include throw ratio, throw distance, and screen width calculators in the projector's user manuals and on their support websites.
Lens Shift (Horizontal/Vertical)