Normal lens
type of photography and cinematography lens
In photography, the phrase normal lens is used for camera lenses that have a focal length which is roughly the diagonal of the image projected inside the camera. Camera lenses with a shorter focal length are called wide-angle lenses, those with a longer one telephoto lenses.
This gives a natural perspective.
| Film format | Image dimensions | Image diagonal | Normal lens focal length |
|---|---|---|---|
| 9.5 mm Minox | 8 × 11 mm | 13.6 mm | 15 mm |
| APS C | 16.7 × 25.1 mm | 30.15 mm | 28 mm, 35 mm |
| 135 | 24 × 36 mm | 43.27 mm | 50 mm, 45 mm |
| 120/220, 6 × 4.5 (645) | 56 × 45 mm | 71.84 mm | 75 mm |
| 120/220, 6 × 6 | 56 × 56 mm | 79.20 mm | 80 mm |
| 120/220, 6 × 7 | 56 × 68 mm | 88.09 mm | 90 mm |
| 120/220, 6 × 9 | 56 × 84 mm | 100.96 mm | 105 mm |
| large format 4 × 5 sheet film | 96 × 120 mm (image area) | 153.67 mm | 150 mm |
| large format 8 × 10 sheet film | 194 × 245 mm (image area) | 312.51 mm | 300 mm |
- In Digital photography the situation is more complex. The sensor type diameter is not the sensor diameter:
- (*) refers to tv-tube diameters that were standards in the 50's. The normal lens focal length is roughly 2/3 of the TV tube diameter.
- (**) this is a mathematical calculation because most of the cameras have zoom lenses.
| Sensor type | TV-tube diameter * | Image dimensions | Image diagonal | Normal lens focal length ** |
|---|---|---|---|---|
| 1/3.6" | 7.1 mm | 4.00 x 3.00 mm | 5.00 mm | 5 mm |
| 1/3.2" | 7.9 mm | 4.54 x 3.42 mm | 5.68 mm | 5.7 mm |
| 1/3" | 8.5 mm | 4.80 x 3.60 mm | 6.00 mm | 6 mm |
| 1/2.7" | 9.4 mm | 5.37 x 4.04 mm | 6.72 mm | 6.7 mm |
| 1/2.5" | 10.2 mm | 5.76 x 4.29 mm | 7.2 mm | 7 mm |
| 1/2" | 12.7 mm | 6.40 x 4.80 mm | 8.00 mm | 8 mm |
| 1/1.8" | 14.1 mm | 7.18 x 5.32 mm | 8.93 mm | 9 mm |
| 1/1.7" | 14.9 mm | 7.60 x 5.70 mm | 9.50 mm | 9.5 mm |
| 1/1.6" | 15.9 mm | 10.5 mm | ||
| 2/3" | 16.9 mm | 8.80 x 6.60 mm | 11.00 mm | 11 mm |
| 1" | 25.4 mm | 12.80 x 9.60 mm | 16.00 mm | 16 mm |
| 4/3" | 33.9 mm | 18.00 x 13.50 mm | 22.50 mm | 23 mm |
| (APS-C) 1/8" | 45.7 mm | 22.70 x 15.10 mm | 27.3 mm | 27 mm |
| DX | n/a | 23.7 x 15.8 | 28.40 mm | 28 mm |
| FF (35 mm film) | n/a | 36 x 24 mm | 43.30 mm | 50 mm |
| (4 x 5 cm) | n/a | 49.0 x 36.7 mm | 61.22 mm |
- In cinematography a focal length roughly equivalent to twice the diagonal of the image projected within the camera is considered normal.
| Film format | Image dimensions | Image diagonal | Normal lens focal length |
|---|---|---|---|
| N-8 | 3.68 x 4.88 mm | 6.11 mm | 12 - 15 mm |
| Single - 8 (FUJI) | 4.22 x 6.24 mm | 7.53 mm | 15 - 17 mm |
| Super - 8 | 4.22 x 6.24 mm | 7.53 mm | 15 - 17 mm |
| 9.5 mm | 6.5 x 8.5 mm | 10.70 mm | 20 mm |
| 16 mm, magnetical sound | 7.49 x 10.26 mm | 12.70 mm | 25 mm |
| 16 mm, optical sound | |||
| 35 mm | 18.00 x 24.00 mm | 30.00 mm | 60 mm |
| 35 mm, sound | 16.03 x 22.05 mm | 40.53 mm | |
| 65 mm | |||
| 70 mm | 52.6 x 23.0 mm | 57.41 mm |