What is Keystone Correction?

Keystone Correction is a common feature on digital projectors that allows the user to adjust the image shape to correct any distortion caused by the angle of projection.

When a projector is required to be placed at an angle, such as angled up to raise the image height, or angled to the left or right to move the image horizontally, the resulted image will appear distorted or skewed. The Vertical Keystone correction will be used to adjust the distortion caused by the up/down angle, while Horizontal Keystone correction will be used to adjust the left/right angle distortion.

As Keystone Correction is a digital adjustment it will result in a loss in resolution when used. A few degrees of keystone correction rarely causes any noticeable reduction in image detail, however increasing the amount of projector angle, and therefore the amount of keystone correction used, will decrease image detail.