Optoma · 5,000–7,999 lumens · 4K
Optoma ZK521ST
5,000lumens
3840×2160native
0.79–0.79throw ratio
3.0 kgweight
The Optoma ZK521ST is a DLP projector rated at 5,000 lumens with a native resolution of 3840×2160. It uses a laser phosphor light source. Its lens has a throw ratio of 0.79:1. Released June 2026.
Throw distance table
Distance from lens to surface for each image width (16:9 (4K HD)). Calculated as throw ratio × width; check the manufacturer's lens calculator before installation.
| Image width | Height | Standard lens 0.79:1 |
|---|---|---|
| 2 m (6.6 ft) | 1.12 m | 1.6 m |
| 3 m (9.8 ft) | 1.69 m | 2.4 m |
| 4 m (13.1 ft) | 2.25 m | 3.2 m |
| 5 m (16.4 ft) | 2.81 m | 4.0 m |
| 6 m (19.7 ft) | 3.38 m | 4.7 m |
| 8 m (26.2 ft) | 4.5 m | 6.3 m |
| 10 m (32.8 ft) | 5.62 m | 7.9 m |
| 12 m (39.4 ft) | 6.75 m | 9.5 m |
| 15 m (49.2 ft) | 8.44 m | 11.9 m |
| 20 m (65.6 ft) | 11.25 m | 15.8 m |
| 25 m (82.0 ft) | 14.06 m | 19.8 m |
| 30 m (98.4 ft) | 16.88 m | 23.7 m |
Open in the throw-distance calculator →
Maximum image size for projection mapping
Largest image that keeps a 10:1 contrast against ambient light on a light, matte surface (80% optical efficiency). See how this is calculated.
| Ambient light | Max area | Max width × height |
|---|---|---|
| Dark rural site (1 lux) | 444 m² | 28.1 × 15.8 m |
| Quiet street at night (5 lux) | 89 m² | 12.6 × 7.1 m |
| Lit city square (15 lux) | 30 m² | 7.3 × 4.1 m |
| Bright urban area (30 lux) | 15 m² | 5.1 × 2.9 m |
| Indoor, lights dimmed (50 lux) | 9 m² | 4.0 × 2.2 m |
Full specifications
| Aspect Ratio | 16:9 (4K HD) |
|---|---|
| Audible Noise | 29 dB / 29 dB (Eco) |
| Best Used For | Higher Education Corporate/Business |
| Brightness | 5,000 Lumens (ISO) 2 |
| Connection Panel | 12-Volt Trigger 3D Sync: BNC Audio In: Mini Jack Audio Out: Mini Jack HDMI 2.0 x 2 Network: RJ-45 RS232: DB-9pin USB (power only): A x 2 |
| Contrast | 300,000:1 (full on/off) |
| Digital Keystone | Horizontal & Vertical |
| Display Type | DLP |
| Dynamic Contrast | 2,000,000:1 |
| Features | Short-Throw 24/7 Operation Geometric Correction |
| Image Size | 40.00" - 300.00" |
| Included Lens | Fixed focal length |
| Input Lag | 4K/60: 16.7ms | 1080p/120: 8.4ms |
| Internal Speakers | 15.0 Watts Mono |
| Light Source | Laser Phosphor |
| MSRP | $2,699 (USD) |
| Projector Size | 4.50" x 10.80" x 8.50" (HxWxD) |
| Released | June 2026 |
| Resolution | 3840x2160 |
| Status | Shipping |
| Street Price | $2,699 (USD) |
| Throw Distance | 2.3' - 17.2' Calculate Throw Distance |
| Throw Ratio | 0.79:1 (D:W) |
| Video Modes | ** |
| Warranty | 5 Years |
| Weight | 6.6 lbs |
Specifications compiled from ProjectorCentral and manufacturer data. Prices change — verify with dealers.
Similar projectors
| Model | Lumens | Resolution | Light source | Throw ratio | Street price |
|---|---|---|---|---|---|
| Optoma HCPro-4400 | 5,000 | 3840×2160 | Laser Phosphor | 1.2–1.92:1 | $5,436 |
| Optoma HCPro-5400 | 5,000 | 3840×2160 | RGB Laser | 1.25–2.0:1 | $7,999 |
| Optoma UHZ5000 | 5,000 | 3840×2160 | Laser Phosphor | 1.2–1.92:1 | |
| Optoma ZK521ST-B | 5,000 | 3840×2160 | Laser Phosphor | 0.79:1 | $2,699 |
| Optoma ZK551 | 5,100 | 3840×2160 | Laser Phosphor | 1.4–2.24:1 | $2,099 |
| LG ProBeam BU50RG | 5,000 | 3840×2160 | Laser Phosphor | 1.3–2.08:1 | $3,399 |
| LG ProBeam BU53RG | 5,000 | 3840×2160 | Laser Phosphor | 0.94–1.14:1 | $4,150 |
| Casio XJ-L8300HN | 5,000 | 3840×2160 | Laser Phosphor | 1.38–2.03:1 | $6,999 |