The difference that matters
The Optoma ZK521ST-B lists higher resolution (4K UHD). The Optoma ZK521ST-B costs $1,301 less at the prices we observed.
Side by side
| Specification | BenQ LU935ST | Optoma ZK521ST-B |
|---|---|---|
| Brightness | 5,500 lm | 5,000 lm |
| Resolution | WUXGA (1920 × 1200) | 4K UHD (3840 × 2160) |
| Native aspect | 16:10 | 16:9 |
| Throw ratio | Not published | 0.79:1 |
| Distance for a 10.5 × 8 ft 4:3 screen | — | 11′ 1″ |
| Brightness on that screen | 55 fL | 45 fL |
| Light source | Laser | Laser |
| Rated life | 20,000 h | 30,000 h |
| Zoom | — | Fixed |
| Lens shift | Vertical and horizontal | Vertical 104–125% |
| Input lag | — | 16.7 ms (4K 60 Hz); 8.6 ms (1080p 120 Hz) |
| Price seen | $4,000 | $2,699 |
Highlighted rows differ. Figures come from each product's sources; room depth, distances and brightness are FOREference calculations using the same method for both.
Which should you choose?
BenQ LU935ST
Choose the BenQ LU935ST if you prefer its maker, seller or ecosystem — the published figures do not favour it.
Optoma ZK521ST-B
Choose the Optoma ZK521ST-B if image detail matters most or price leads the decision.
Before you buy either
- Check the room: room size calculator and ceiling height calculator.
- Confirm what each seller includes — accessories, software trials and bundles change often.
- Read the limitations on each full reference page.
FOREference compares published specifications; we have not tested these products side by side. How we work · Disclosure