Keystone border ghost?


I have a question I can't seem to find an answer to.

I've seen a xgimi horizon pro in action and when it was auto keystone it produced a horrible ghosted image of the original screen around the keystone part.

My question is do ust laser projectors suffer this? I'm looking mostly at the new xgimi aura but would be willing to spend a little more.

I'm creating a dedicated room but only have 9 feet of tbrow distance so think a ust might be my best option, also looking for something with good blacks.



Well-known Member
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Keystone is as much an enemy to image quality as is daylight to projectors and you'd be better off adjusting the projector to remove it as best you can than taking the short cut with this technology.

We have a couple of UST projectors in our showroom and both are quite amazing at what they do. As they are both on a top which is level, I cannot say I've noticed any issues with a trapezoid effect which many feel makes then require using keystone

I'm guessing the projector is either pointing upwards or downwards to hit the screen with you using keystone. If that's the case, using a projector with a good lens shift will reduce this if you are still wishing to use it at the back of the room otherwise, I've been very impressed with the Hisense 120L5FT and even though it comes with free installation plus a 120 ALR screen, it still commands a good price point leaving some great rear projector options open to you
Thanks for the reply.

I think UST is my only option right now. I've looked hard at the BenQ 7050i the optmoa P2 and ls500.

It appears the benq may be the one to get st the moment, decent blacks and exceptional color accuracy, also does 3d but I need to confirm if I can manually do side by side 3d viewing before I purchase.


Active Member
Keystone should always be a last resort after using all lens shift, projector positioning, and shimming of furniture etc available to you

Once you have to use keystone, even the best projectors are going to show some halo/ghosting. Upgrading to a better projector can help a little, but beyond that point the only real solution is to add black velvet around the screen to absorb and scatter the light


Novice Member
Keystone is digitally altering the image in an attempt to match the image with the screen, it does not change anything about the projected light itself. So the "grey border" is normal, when the projector's contrast ratio is low, it is more obvious because the projector can not offer a decent level of black. Always avoid keystone/digital zoom if you can, it will reduce the image quality for sure and cause the annoying "grey border". The possible way to hide the "grey border" will be adding LED background light around the screen so the LED light will dissolve/hide the "grey border".

For UST projectors, because UST will need to be placed at the center of the screen, so the reality is you do not need keystone adjustment at all in the first place, so there won't be a such problem. BUT, if you do use keystone adjustment on UST for a quick alignment of the screen, you will suffer from the same "grey border" issue. With UST, it is worthy to spend a few more time adjusting the physical position of the projector to precisely align the screen, by doing so, you will get a perfect image without any distortion/"grey border"/soft focus issue.

Again, avoid keystone adjustment if you can, no matter it is a UST or standard/long throw projector.


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