Setting up a projector seems like an easy task for most people — all it takes is to pop in the projector display cable to your computer, fire up your content, and enjoy watching anything on a projector screen or wall. But often convenience doesn’t exactly equate to setup speed, as some projectors tend to display oddly-shaped images if not configured correctly. This is where the lens shift feature comes to the rescue, a nifty feature of most modern projectors designed to display the perfect-sized projector image without any distortions or image compression issues.
What is projector lens shift?
The projector lens shift, or simply lens shift, is a projector feature that compensates for geometrical differences in installations, and “shifts” the image in horizontal and vertical directions through optical movement of the projector lens itself. This allows for complex installations such as overhead projectors, where the image might get distorted due to the relative position of the projector towards the screen or wall.
By employing a hardware-based shifting of the projector image, lens shift enables the image to be projected as if the projector sits on a flat surface — there is no need for keystone corrections (more on this later) or manually tilting the projector. In addition to its main ability to render images without distortion or compression, lens shift also opens up a bonus feature that lets the viewer perceive every part of the image in the “sweet spot”, that is making the image appear even, well-proportioned, bright, and clear in every direction.
Lens shift vs. keystone correction
While most projectors feature keystone correction, a method that uses algorithms to fit the projected image onto a wall or screen even with the projector positioned on an angle, it basically manipulates the image to fit on a wall or screen in relation to its aspect ratio with a bit of compromise. Since keystone correction uses software to modify the image to fit, it tends to produce compressed images resulting in blurs or lower-resolution images in some areas of the projected image. Distortions to the image are visible on the corrected edges of the image.
What lens shift does in contrast to keystone correction is that it sets up the lens to project the image at a position that is adapted from the projector’s position itself, requiring no manual adjustments or tilting from the user. In addition, it doesn’t make use of software to correctly display the image — some projectors offer a convenient dial, a knob, or a remote-controlled power adjustment (in some high-end projectors) to change the position of the image as the user sees fit. Lens shift can be used to lower, raise, tilt, or move the projected image without having to change the position of the projector itself.
Do you need lens shift on your projector?
Lens shift offers a convenient way for you to set up your projector in even the most difficult installation configurations. It is important to know the type of installation you will have, as this feature might not be necessary for some uses. If you don’t see setting up a projector in hard-to-reach places or at an angle, lens shift might not be a needed feature. In this case, the keystone correction feature might offer a more reasonable compromise in budget projectors. However, if you prefer minimal image distortions with the same image quality you’d expect from a monitor screen, the lens shift feature might be of your interest on your next projector purchase.