Short Throw vs UST: Which projector to choose?

Short Throw vs UST: Which projector to choose (and when it's worth it)

If you want a large image without hanging a projector from the ceiling , you'll have two options: short throw or UST (ultra short throw, like "laser TV"). The right choice depends on the space, the screen, and the ambient light.

1) What is UST and why do you need a specific screen?

UST sits a few centimeters from the wall/screen and projects the light at a very steep angle. Therefore, the screen has to be designed to reflect the projector's light towards the viewer and reduce ambient light coming from above.

In practical terms: with the lights on, a normal screen can leave the image "dull/washed out" , while a UST/ALR screen greatly improves the perception of contrast.

2) Short Throw: when it makes the most sense

Short throw projects big up close, but typically still requires more “traditional” positioning than UST. It’s a good choice when:

  • Do you want to reduce shadows?

  • You want flexibility,

  • And you don't want to invest in a UST setup + UST-ALR/CLR screen right away.

Elite Screens summarizes the differences between standard/short/UST and notes that UST-ALR/CLR materials are "specialty" for UST.

3) Throw ratio: the number that governs the installation.

Throw ratio determines whether the projector "fits" in your room for the desired image size. ProjectorCentral explains the relationship between distance and size and provides a calculator for each model.

UmBox tip: before you buy, measure:

  • Available distance from the projector to the screen,

  • desired size (e.g., 100", 120")
    and validates the model calculation.

4) ALR/CLR: when it's worth it (and when it's not)

ALR (Ambient Light Rejecting) works by preferentially reflecting the projector's light towards the audience and deflecting ambient light.
For UST lighting, the ideal choice is a specific ALR/CLR for UST lighting , because the light geometry is different.

5) Lens shift vs. Keystone: avoids loss of quality.

Keystone correction is a digital correction that can reduce brightness and quality because it "wastes" part of the chip/usable area.
Whenever possible, prioritize:

  • good positioning,

  • lens shift (physical adjustment),

  • and avoids relying on keystone trading.

FAQ

Can I use a regular screen with UST?
It works, but in ambient light the image tends to look "washed out"; UST screens help reject light and improve the perceived image.

What is throw ratio?
It's the ratio between the distance and width of the image; it determines the possible size in your room.

Is Keystone bad?
It's useful in emergencies, but it can reduce brightness/quality. Lens shift/positioning is better.