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 portable 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.

How Does 2D Keystone Correction Adjust Distorted Images

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.

Vertical keystone distortion and correction

Horizontal keystone distortion and correction

When Should Keystone Correction be Used?

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 portable 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.

How Does Keystone Correction Affect Picture Quality

But here's the catch: keystone correction isn't without its side-effects and not all correction tech is created equally. The software behind the scenes must crop, magnify, and refine in ways that can slightly impair image quality or add pesky shadow-like 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.

Keystone cropping and removing redundancies in the image may result in the image having border shadows.

keystone correction isn't without its side-effects

The projector ends up utilizing only a portion of the total available pixels for the corrected side, leading some light and pixels to go to waste as black "space," which impacts image 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.

How BenQ Optimizes Auto Keystone Correction with Time-of-Flight (ToF) Technology

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.

BenQ’s Auto 2D Keystone powered by ToF

Additional Keystone Correction FAQs about GP100

Learn more

Q: How do I activate Keystone Correction on my GP100?

There are two main ways to activate Auto Keystone on the GP100. Activate it manually by pressing the “Geometry setting” button on your remote, or automatically by moving the projector and triggering the G-Sensor.

Q: Why doesn’t Auto Keystone work properly on my GP100?

As useful and advanced as it is, Auto Keystone Correction is not a perfect technology. Factors such as projection angle, distance, and the setting will affect Auto Keystone Correction’s ability to fix a distorted image.

Speaking of angles and distances, here's a tip: For a 100-inch screen with Auto 2D Keystone to work properly, keep your projector tilted horizontally within 20 degrees in 2.90 meters away. The same goes for vertical tilting within 13 degrees.

Generally, with the projector at a 0-degree angle, it's about 2.65 meters away from the wall to display a 100-inch screen.

When the projection angle turns horizontally within 20 degrees, auto keystone correction works properly. The projector should be about 2.90 meters away from the wall to display a 100-inch screen.

When the projection angle turns vertically within 13 degrees, auto keystone correction works properly. The projector should be about 2.90 meters away from the wall to display a 100-inch screen.

Note: If a larger adjustment angle is needed or it exceeds the distance range mentioned above, manual adjustment is required.

Q: Can I make manual keystone adjustments for refinement?

Absolutely. If you need a bigger adjustment or you're outside those ranges, manual adjustments are your friend. Lastly, be mindful of your surroundings. Too much light or an unreflective screen can mess with your ToF sensor's readings.

Q: Does Keystone Correction impact the projector’s input lag/latency?

Short answer, yes. When you use keystone correction, it can slightly increase your projector's input lag, making it a bit slower. So, if you're gaming and want that low input lag, turn off Auto Keystone and set your 2D Keystone Correction values to zero.

With all this knowledge, you'll be a projector pro in no time, getting the perfect image every time, you use your portable projector. Enjoy your movie nights and gaming sessions without those pesky trapezoids!

Strictly necessary cookies

Functional cookies

Performance cookies and advertising cookies

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