Optoma 4K400STx: Specs, Throw Distance & Alternatives
A short-throw 4K UHD DLP lamp projector with a game mode. Optoma rates it at 4,000 lumens, and ProjectorCentral lists 4.2 ms input lag at 1080p/240. It has a fixed 0.5:1 lens, no lens shift, no smart TV system and no wireless listed.
Is the Optoma 4K400STx right for you?
Good for
- High-refresh PC gaming at 1080p/240 (listed at 4.2 ms)
- Small rooms: a 0.5:1 short-throw lens, with a 100-inch image from about 3.6 ft
- HDR10 and HLG content
- External sound: 3.5 mm and S/PDIF optical audio outputs
What to plan for
- The 4.2 ms figure is for 1080p/240 only: no 4K/60 or 1080p/60 lag figure is published
- No built-in streaming or wireless listed: add a streaming stick (the USB-A port supplies 1.5 A of power)
- No lens shift and no optical zoom, so placement has to be planned
- Both HDMI ports are HDMI 2.0, not 2.1
- Lamp rated for 4,000 hours in Bright mode (15,000 in Dynamic mode, per Optoma)
Based on manufacturer specifications and published reviews (sources below). We don't do hands-on testing.
Optoma 4K400STx specs
| Resolution | 4K UHD (3840 × 2160, single-chip DLP) |
|---|---|
| Brightness | 4,000 lumens (Optoma rating; ProjectorCentral lists it as ISO 21118) |
| Display technology | DLP |
| Light source | Lamp (240 W) |
| Lamp life (Bright mode) | 4,000 hours |
| Contrast ratio | 1,000,000:1 (Optoma rating) |
| Throw ratio | 0.5:1 |
| Lens shift | None (fixed lens, no optical zoom) |
| Max refresh rate | 240 Hz |
| HDMI ports | 2 (HDMI 2.0) |
| Speakers | 10 W |
| Weight | 8.77 lb |
How far from the screen?
Lens-to-screen distance for a 16:9 image, calculated from its 0.5:1 throw ratio. The lens is fixed, so the distance sets the image size.
| Screen | Distance |
|---|---|
| 80″ | 2' 11" |
| 100″ | 3' 8" |
| 120″ | 4' 4" |
| 150″ | 5' 5" |
Optoma 4K400STx input lag by mode
| Signal | Input lag |
|---|---|
| 1080p / 240 Hz | 4.2 ms |
Source: ProjectorCentral’s listing of Optoma’s rating (Optoma’s spec table rounds it to 4 ms); no 4K/60 or 1080p/60 figure is published and we found no independent measurement. Its fastest figure (4.2 ms at 1080p / 240 Hz) is quicker than 77 of the 96 projectors with a lag figure in our input lag database, which lists each model's fastest mode.
Optoma 4K400STx alternatives at a similar price
In-stock 4K projectors priced closest to it on Amazon today.
| Model | Price today | Amazon rating | Compare |
|---|---|---|---|
| Optoma 4K400STx (this one) | $1,807 | 2.9★ | — |
| BenQ X3100i True 4K UHD 4LED Gaming Projector | $1,799 | 3.6★ | — |
| ViewSonic LS740-4K 4K UHD 5000 Lumens Laser Projector | $1,796 | — | — |
| BenQ TK700STi 4K HDR Short Throw Gaming Projector | $1,899 | — | — |
| Nebula X1 4K Projector by Anker | $1,899 | 4.4★ | — |
Where it fits
Optoma 4K400STx FAQ
- How far from the screen should the Optoma 4K400STx be for a 100-inch image?
- About 3' 8" from lens to screen. It has a fixed 0.5:1 lens, so each screen size has one distance.
- What is the input lag of the Optoma 4K400STx?
- 1080p / 240 Hz: 4.2 ms. Source: ProjectorCentral’s listing of Optoma’s rating (Optoma’s spec table rounds it to 4 ms); no 4K/60 or 1080p/60 figure is published and we found no independent measurement.
- Does the Optoma 4K400STx have lens shift?
- No. It has a fixed 0.5:1 short-throw lens with no lens shift and no optical zoom, so the image size and position are set by where the projector sits.
Sources
Price, stock and rating come from Amazon and update automatically (last checked Nov 14, 2026, 8:00 PM).
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