Table of F-stops|
f-stops are the ratio of focal length to the effective aperture of the lens. In other words at f-stop f1 the focal length equals the effective aperture. As you stop down the intensity of the light falls off with ratio of the square root of 2. By convention f-stops are rounded off to convenient values. |
|
| f-stop | True f-stop |
| f1 | 1 |
| f1 ¼ | 1.09 |
| f1 ½ | 1.19 |
| f1 ¾ | 1.3 |
| f1.4 | 1.41 |
| f1.4 ¼ | 1.54 |
| f1.4 ½ | 1.68 |
| f1.4 ¾ | 1.83 |
| f2 | 2 |
| f2 ¼ | 2.18 |
| f2 ½ | 2.38 |
| f2 ¾ | 2.59 |
| f2.8 | 2.83 |
| f2.8 ¼ | 3.08 |
| f2.8 ½ | 3.36 |
| f2.8 ¾ | 3.67 |
| f4 | 4 |
| f4 ¼ | 4.36 |
| f4 ½ | 4.76 |
| f4 ¾ | 5.19 |
| f5.6 | 5.66 |
| f5.6 ¼ | 6.17 |
| f5.6 ½ | 6.73 |
| f5.6 ¾ | 7.34 |
| f8 | 8 |
| f8 ¼ | 8.72 |
| f8 ½ | 9.51 |
| f8 ¾ | 10.37 |
| f11 | 11.31 |
| f11 ¼ | 12.34 |
| f11 ½ | 13.45 |
| f11 ¾ | 14.67 |
| f16 | 16 |
| f16 ¼ | 17.45 |
| f16 ½ | 19.03 |
| f16 ¾ | 20.75 |
| f22 | 22.63 |
| f22 ¼ | 24.68 |
| f22 ½ | 26.91 |
| f22 ¾ | 29.34 |
| f32 | 32 |
| f32 ¼ | 34.90 |
| f32 ½ | 38.05 |
| f32 ¾ | 41.50 |
| f45 | 45.25 |