The values below are calculated by the formula offered by Bob Dome:
______
R = V WCF
where R = radius of aperture
W = wavelength of light
C = constant
F = focal length
The focal length is determined by dividing the focal length by the pinhole diameter.
| Focal Length | Pinhole Diameter | F Stop |
|---|---|---|
| 10 | .118 | 84 |
| 20 | .16 | 120 |
| 30 | .20 | 146 |
| 40 | .23 | 163 |
| 50 | .26 | 189 |
| 60 | .29 | 207 |
| 70 | .31 | 224 |
| 80 | .33 | 240 |
| 90 | .35 | 254 |
| 100 | .37 | 267 |
| 110 | .39 | 281 |
| 120 | .40 | 293 |
| 130 | .42 | 305 |
| 140 | .44 | 317 |
| 150 | .45 | 328 |
| 160 | .47 | 338 |
| 170 | .48 | 349 |
| 180 | .50 | 359 |
| 190 | .51 | 369 |
| 200 | .52 | 378 |
| 210 | .54 | 387 |
| 220 | .55 | 397 |
| 230 | .56 | 406 |
| 240 | .57 | 415 |
| 250 | .59 | 423 |
| 260 | .60 | 431 |
| 270 | .61 | 440 |
| 280 | .62 | 448 |
| 290 | .63 | 456 |
| 300 | .64 | 464 |
| Focal Length | Pinhole Diameter in 1/1000ths |
F Stop |
|---|---|---|
| 1 | 7.4 | 135 |
| 2 | 10.5 | 190 |
| 3 | 12.8 | 234 |
| 4 | 14.8 | 270 |
| 5 | 16.6 | 301 |
| 6 | 18.2 | 330 |
| 7 | 19.6 | 357 |
| 8 | 21.0 | 381 |
| 9 | 22.2 | 405 |
| 10 | 23.5 | 426 |
| 11 | 24.6 | 447 |
| 12 | 25.7 | 467 |
| 13 | 26.7 | 487 |
| 14 | 27.7 | 505 |
| 15 | 28.7 | 523 |
| 16 | 29.7 | 538 |
| 17 | 30.6 | 556 |
| 18 | 31.5 | 571 |
| 19 | 32.3 | 588 |
| 20 | 33.2 | 602 |
| 21 | 34.0 | 618 |
| 22 | 34.8 | 632 |
| 23 | 35.6 | 646 |
| 24 | 36.3 | 661 |