Our take
The BenQ SP840 combines a native 1920 × 1080 DLP image with a 4,000 ANSI-lumen rating, dual HDMI, a manual 1.2× zoom, and a conventional 1.62–1.92:1 throw. BenQ lists a 300 W lamp and a 3,000:1 contrast ratio. The strongest case for it is a bright, wired Full HD setup whose room geometry can be measured in advance. The saved exact-model sheet establishes useful display facts but does not settle whether a particular buyer should treat it primarily as a home-theater or presentation model, so judge the actual room and source needs.
A fixed, source-connected room where native Full HD and a bright rated image matter and a power outlet and conventional projector distance are available.
It is not a cordless or ultra-short-throw choice, and a used unit should not be selected from the rated lamp output alone. Buyers seeking laser lighting, integrated streaming, or a verified current package should compare other models.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- Native Full HD gives source detail that is visibly more useful for modern video than XGA or SVGA.
- BenQ labels 4,000 lumens ANSI, so the rating has a stated method instead of an unqualified lumen figure.
- Two HDMI inputs and manual zoom provide practical connection and framing choices for a fixed room.
What to weigh up
- A 300 W lamp creates a maintenance item, and the datasheet's rated output cannot establish the brightness of a used lamp.
- The 1.62–1.92:1 throw is conventional; it is not a close-wall substitute for a short-throw or UST model.
- No saved exact-model source establishes built-in streaming, battery use, lens shift, or a specific primary use category.
Specifications and exact model details
The key details
| Model covered | SP840 |
|---|---|
| Image format | Native 1920 × 1080 Full HD DLP |
| Rated light output | 4,000 ANSI lumens, manufacturer rated |
| Placement | 1.62–1.92:1 throw with manual 1.2× zoom |
Performance figures are manufacturer claims. Source checked October 15, 2026. Regional models and included accessories can differ.
Full review: how the features affect your choice
What the features mean for you
Native Full HD is the main detail advantage
BenQ identifies the SP840 as a 1080p DLP projector with a native 1920 × 1080 image. That makes it a stronger match for widescreen video than the XGA and SVGA lamp models in this batch. Input compatibility alone is not the same thing as native resolution, so the panel specification is the useful comparison point when fine text, subtitles, or high-definition sources matter. The datasheet does not establish how a particular used unit is aligned or focused, so inspect a test image across the full screen before committing to a permanent mount.
Treat the ANSI rating as a model specification
BenQ lists 4,000 ANSI lumens and a 3,000:1 contrast ratio. Those are manufacturer specifications, not a measurement of an individual projector after years of lamp use. The ANSI label makes its stated light output more comparable than a bare lumen claim, while room light, screen size, image mode, lamp mode, and screen surface still shape the result. Ask for the lamp counter on a used unit and check for uneven color or dim areas. A bright rating cannot compensate for poor placement, a worn lamp, or a screen that is too large for the room.
Measure throw before planning the furniture
The datasheet gives a 1.62–1.92:1 projection ratio and a manual 1.2× zoom. That adjustment gives some framing room, but it does not make the SP840 a short-distance projector. Measure the lens-to-screen distance against the intended diagonal and leave room for the chassis, ventilation, and cable bend. Manual zoom also means the installer adjusts the lens at the projector rather than from a motorized seat position. If the projector must sit close to the wall or above a narrow shelf, compare a model documented for that placement instead of trying to correct a mismatched distance electronically.
A wired source plan suits its documented inputs
BenQ lists dual HDMI among the SP840 connections, making it straightforward to plan a modern external video source without relying on built-in apps. The saved datasheet does not establish an integrated streaming platform or wireless operating system. A receiver, game console, computer, or separate streaming device can supply content through the documented inputs. Confirm that the exact unit accepts the resolution and refresh rate of the intended source, and check that each port works. The article does not treat an HDMI connection as evidence that apps run on the projector itself.
Lamp service and package condition matter
BenQ specifies a 300 W lamp and listed Normal and Eco life of 2,000 and 3,000 hours. These are model-level reference figures, not a promise about a used lamp. A buyer should request the displayed lamp hours, confirm whether the counter was reset after a genuine replacement, and inspect the filter and airflow path. Check that the remote, power cord, and any source adapters are actually included. The support page helps identify manuals for the SP840, but it cannot verify the history or present condition of a particular secondhand item.
Compare for your needs
Epson LS11000 offers laser lighting and pixel-shifted on-screen 4K; Sony VPL-HW30AES is a Full HD home-cinema lamp option with a non-ANSI light rating.
Find the video projector that fits you.
Tell us what matters. We’ll help you weigh the options.
Before you buy
Is the SP840 a native 1080p projector?
Yes. BenQ's exact SP840 datasheet specifies native 1920 × 1080 DLP resolution.
Are its 4,000 lumens ANSI?
BenQ labels the SP840 output as 4,000 ANSI lumens; that remains a model rating, not a used-unit measurement.
Can the SP840 sit close to the wall?
Its 1.62–1.92:1 throw is conventional, so measure the room rather than treating it as a UST projector.
Where can I check the current price?
Use the Amazon link for current offers. Check the exact model, seller, product condition, delivery, and return terms. This page does not display a live price or confirm stock.
Sources and review basis
Sources & review basis
We use the linked product documentation for the features above. Our suitability notes and buying advice are editorial judgments based on those features, not measured performance results.
- BenQ SP840 model datasheet ↗ — checked October 15, 2026.
- BenQ SP840 datasheet ↗ — checked October 15, 2026.
- BenQ SP840 support and manual page ↗ — checked October 15, 2026.
The decision
Choose SP840 when its ANSI-rated output, native Full HD image, working lamp, and conventional throw all fit the measured room.
Is it the right fit?
Check the exact model and today’s offers on Amazon.