Optoma ZK521ST-B 4K Laser Projector vs Optoma ZK431ST-B Projector

Both are Optoma 4K laser short-throw projectors built for golf sims, so the choice comes down to brightness versus throw distance. The ZK521ST-B is the brighter unit at 5,000 lumens and suits larger screens and rooms with more ambient light. The ZK431ST-B is dimmer at 4,100 lumens but throws from closer at a 0.496:1 ratio, which cuts player shadows in tight bays and adds Smart Fit auto alignment. Owners of both report the laser source holds up to always-on use; the ZK521ST-B is the safer pick for big commercial bays, the ZK431ST-B for small home rooms.

• Choose the Optoma ZK521ST-B if you have a large screen or a room with daylight and need the extra brightness.
• Choose the Optoma ZK431ST-B if your bay is short on depth and you want the closest throw and automatic screen alignment.