Optoma ZK431ST 4,100 Lumens 4K Short-Throw Laser Projector with Network Control

Optoma ZK431ST – 4K short-throw laser projector with full LAN remote management for continuous operation

The Optoma ZK431ST combines two planning advantages in one unit: it projects a 4K UHD image (3,840 × 2,160) from a short distance (a 100" image from just around 1.10 m away) and can be fully managed remotely and monitored during operation via LAN. With 4,100 ANSI lumens from a maintenance-free light source, 24/7 rating, an IP6X-sealed optical unit and 360° and portrait mounting, it is aimed at AV integrators and IT departments that need a sharp 4K image and central control in continuous operation in cramped conference rooms, training centres and signage installations.

Key benefits at a glance

• 4K UHD (3,840 × 2,160) on a large surface: presentation text, architectural plans and UHD video remain sharp and legible even on wide image sizes
• Short-throw lens (TR 0.496:1, fixed): 100" image from around 1.10 m wall distance, where standard projectors would have no throw distance
• Full network control via LAN: central remote management and status monitoring without walking to the unit
• 4,100 ANSI lumens laser light: clearly legible even in daylight and with the ceiling lights on
• Maintenance-free light source with 30,000 hours service life: usable for more than ten years at 8 hours of operation a day
• 24/7 rating and IP6X-sealed optical unit: for uninterrupted continuous operation in fixed installations
• 360° installation and portrait mode: portrait-format projection and mounting at any angle, even upside down

Is the Optoma ZK431ST the right choice?

• Yes, for centrally managed 4K fixed installations in conference, training and signage environments with limited wall distance, connection to Crestron/PJLink control systems and 24/7 continuous operation.
• Not ideal, if an interchangeable lens or more installation flexibility when mounting is required. In that case, the higher installation projector class is the better fit.
• Not suitable, if you want to project from a conventional distance: the ZK431ST is designed for short throw and stands around 1.10 m from the wall for 100 inches. If you are planning with a normal room distance, you will find suitable units under 4K projectors.

Unsure about wall distance or control integration? Get in touch → We will plan a matching screen and ceiling mount at the same time.

Short throw as an installation USP: a large image with little wall distance

The fixed TR of 0.496:1 solves one of the most common planning hurdles in fixed installations: rooms without sufficient throw distance for standard projectors. The ZK431ST throws a 100" image (2.21 m image width) from just around 1.10 m away. The short distance also reduces shadows cast by presenters: anyone standing close to the screen leaves the projection cone before blocking the image. For front projection on stages, trade fair stands with no space behind and classrooms with tight ceiling mounting, this is the decisive advantage.

The fixed short-throw lens keeps the image sharp across the entire surface and needs no moving zoom mechanism. The native image offset of 114 % raises the projected image above the lens axis, so the projector can be placed just below the bottom edge of the screen or at table height without protruding into the image – plan the mount height accordingly. Any remaining deviations are corrected by ±15° keystone correction and 4-point correction (Corner Fit).

Picture quality: 4K UHD, 4,100 ANSI lumens and HDR

The Full HD DMD chip uses XPR pixel shift to create 4K UHD resolution of 3,840 × 2,160 pixels, so text, charts and richly detailed video images appear sharp with stable contours on large image sizes. The ZK431ST achieves its dynamic contrast of up to 300,000:1 via DynamicBlack laser modulation, which reduces the light depending on the scene and renders dark image areas with more depth. HDR support adapts highlights and mid-tones to the projector's brightness, and wall colour adjustment corrects the image when projecting onto surfaces that are not pure white.

Network integration and remote management

Central remote management is the ZK431ST's core argument for fixed installations. Via the LAN web interface, IT can switch the projector on and off, adjust brightness and contrast, monitor operating status and install firmware updates without walking to the unit. PJLink (Class 1), Crestron, AMX and Extron are available for connection to professional room control systems, supplemented by an HTTP API and Telnet for custom control logic. The Optoma Management Suite (OMS) also allows cloud-based real-time monitoring and management of the projector. For roll-out, the keypad lock disables operation on the unit, while direct power-on and signal power-on start the projector automatically when mains power is applied or an HDMI signal is detected.

Connections

Connections at a glance:

HDMI 2.0 (2×, 1× with eARC)

Two sources in parallel, such as a media player and a notebook, can stay permanently connected; the eARC port passes the sound losslessly to an AV receiver or soundbar. Sources are switched via remote control or HDMI-CEC.

USB Type A (2×, 1× with 5 V / 1.5 A)

Power supply for an external casting receiver directly on the projector, plus media playback and firmware/logo uploads via USB stick.

Audio out 3.5 mm jack

Connection for active speakers or an external system. The internal 15 W mono speaker only provides basic sound for speech.

LAN (RJ-45)

IP remote control and management: for protocols and functions, see the section "Network integration and remote management" above. Video and audio signals continue to run via HDMI.

RS-232

Serial control with a documented command set for power, picture settings and projector ID; the classic interface for control racks without IP connection.

12 V trigger

DC switching signal that lowers a motorised screen in sync with the projector being switched on.

Security Kensington + PIN

Kensington lock slot and PIN lock secure the unit in publicly accessible rooms.

Light source and operation

This keeps running costs predictable over the entire service life: no filter maintenance and constant brightness throughout.

Mounting and installation

The mechanical requirements for a fixed installation are fully covered: M4 threads with 10 mm screw-in depth for classic ceiling mounts, low weight for simple wall arms, and 300 mm lateral and 100 mm top ventilation clearance. The IP6X seal protects the optical unit against dust, and high-altitude mode keeps operation stable up to 2,500 m. Table and ceiling mounting, 360° orientation and portrait operation are all possible without restriction.

Dimensions & weight: 274 × 114 × 216 mm (W × H × D), 2.9 kg.

Throw distance by image size

The calculated throw distances are based on the manufacturer's fixed TR and serve as guide values. As measuring points (e.g. from the lens centre vs. the front of the housing) can vary between data sheets, calculations accurate to the centimetre cannot always be guaranteed.

In the box

• Optoma ZK431ST (projector with fixed short-throw lens)
• Power cable
• Remote control incl. 2× AAA batteries
• Quick start guide

Optoma ZK431ST vs. BenQ LK830ST vs. BenQ LK835ST – which 4K short-throw laser suits you?

The Optoma ZK431ST is the natural choice when central remote management with a broad, documented control stack (PJLink, Crestron, HTTP API, etc.), the longest maintenance intervals with 30,000 hours of laser runtime and installation-hardened features such as IP6X, 24/7 rating and portrait/360° mounting are what count. The BenQ LK830ST shares the same fixed throw (TR 0.496:1) and is suitable if a BenQ environment is already in place. The BenQ LK835ST offers more positioning flexibility with a motorised 1.2x zoom and autofocus at a slightly greater wall distance; both are good alternatives when their respective focus takes priority.

Have you thought of everything?

• Screen: for a 100-inch diagonal, a high-quality matte white screen with gain 1.0; for bright rooms with ambient light, an ambient light rejecting screen (ALR)
• Ceiling mount with M4 fitting: see projector ceiling mounts
• HDMI cable: for 4K@60 Hz, a High Speed or Premium High Speed HDMI cable; from around 5 to 7 m, an active or optical HDMI cable makes sense for 4K, as the higher bandwidth limits the range of passive cables sooner than with Full HD: HDMI cable category
• External speakers for intelligible speech reinforcement: the celexon active speaker set; for higher-quality conference audio systems, the Kindermann FleX series can be added
• Wireless presentation for BYOD: a receiver from the category Wireless presentation adds AirPlay and Miracast to the HDMI input

Frequently asked questions about the Optoma ZK431ST

How do I integrate the ZK431ST into a central AV control system?
Via LAN with the common control protocols (PJLink, Crestron, AMX, Extron) or the HTTP API; for classic control racks, RS-232 is also available. The web interface handles status queries and firmware updates.

How much wall distance do I need for a particular image?
With the fixed TR of 0.496:1, there is exactly one distance for each image size – a 100-inch image from around 1.10 m. You will find the complete values in the table "Throw distance by image size".

How do I mirror a laptop or smartphone wirelessly?
Video and control signals run via HDMI and LAN; Wi-Fi is not integrated as standard. For wireless mirroring, a system for wireless presentation on the HDMI input adds AirPlay and Miracast.

Conclusion

The Optoma ZK431ST solves two planning problems in one unit: 4K sharpness with minimal wall distance and central network management for continuous operation. This makes it the right choice wherever a sharply projected large image is required in cramped rooms and building services want to integrate the projector into room control via LAN. For a tailor-made configuration of projector, screen, mount and control, our specialist advisors will be happy to help by phone, WhatsApp or e-mail: Request a complete solution →.