Get the Most Out of Your Portable Projector: Easy Keystone Correction for Perfect Projection

Few projection issues are as distracting as the keystone effect that makes images show up as a distorted trapezoid instead of a crisp rectangle. It happens when your projector’s lens isn’t perfectly aligned with the surface you’re projecting onto and requires keystone correction. Formerly a tedious manual task, most projectors these days have built-in technology, typically 2D keystone correction.

For a clear understanding of the trouble, the tech, and how to get beautifully squared images from your projector, read on.

So, how does 2D keystone correction work? Digital distortion is adjusted along vertical and horizontal axes to correct for a misaligned lens. This linear correction results in pixels falling neatly into line as a crisp, clear display and your movie night or special event looking as great as you hoped it would.

With 2D keystone correction, you manage the whole process with a few clicks. Simply adjust one edge of your image until it matches the other edge, and presto! No more trapezoid effect.

Keystone correction is necessary almost any time you’re unable to set up your projector in an ideal, centered position. This happens surprisingly often. Sometimes, you'll have to go with a side projection setup, where your projector sits to the left or right of the screen. For example, you might have your projector next to the sofa or on a shelf near a corner. In such cases, keystone correction is your best option to combat that distortion.

Here's the catch: Keystone correction isn’t without its side effects, and not all correction technologies are created equally. The software behind the scenes has to crop, magnify, and adjust the image, which can slightly impair picture quality and may even introduce shadow-like gray borders.

The reason for these issues is that to fit the trapezoidal image into a neat rectangle, the corrected side's pixels have to squeeze into a smaller space. This means your projector ends up using only a fraction of the available light and pixels for the corrected side. That reduction in pixel usage can cause a dip in quality.

Not to worry, these problems aren't the projector's fault – it's just how the software works. And, even accounting for this possible trade-off, keystone correction is still your best bet to get a consistently square image, especially when dealing with side projection.

In response to frustration with existing keystone correction technologies, BenQ developed an elevated Auto Keystone Correction feature, powered by Time-of-Flight (ToF) technology. This goes beyond the usual 2D correction, refines images better, and is super convenient. ToF technology lets the projector measure distances and depths lightning-fast, with incredible precision and minimal energy use. It's the same tech found in smartphones and laptops that makes them super interactive. BenQ uses this tech to make Auto Keystone Correction a breeze.

With intuitive ToF technology, BenQ's Auto Keystone Correction adjusts image automatically whenever you move your projector. No need to fiddle with menus or buttons – it just works like magic.