| Diameter (mm) | Average day lighting factor (%) | Average illumination (lx) |
| 500 | 0.21 | 28.15 |
| 600 | 0.28 | 37.56 |
| 700 | 0.36 | 48.55 |
| 800 | 0.45 | 60.38 |
| 900 | 0.55 | 73.81 |
| 1000 | 0.66 | 88.55 |