Depth of field by subject distance#
40 mm at f/1.4 on Micro Four Thirds (17.3×13 mm), circle of confusion 15 µm. “Background blur” is the size of an out-of-focus light at infinity as a percentage of frame width.
| Focus distance | Near limit | Far limit | Total DoF | Front / behind | Background blur |
|---|---|---|---|---|---|
| 30.0 cm (0.98 ft) | 29.9 cm | 30.1 cm | 0.2 cm | 50% / 50% | 25.41% |
| 50.0 cm (1.64 ft) | 49.7 cm | 50.3 cm | 0.6 cm | 50% / 50% | 14.36% |
| 75.0 cm (2.46 ft) | 74.3 cm | 75.7 cm | 1.4 cm | 50% / 50% | 9.30% |
| 1.00 m (3.28 ft) | 98.8 cm | 1.01 m | 2.5 cm | 49% / 51% | 6.88% |
| 1.50 m (4.92 ft) | 1.47 m | 1.53 m | 5.8 cm | 49% / 51% | 4.52% |
| 2.00 m (6.56 ft) | 1.95 m | 2.05 m | 10.3 cm | 49% / 51% | 3.37% |
| 3.00 m (9.84 ft) | 2.89 m | 3.12 m | 23.3 cm | 48% / 52% | 2.23% |
| 4.00 m (13.1 ft) | 3.80 m | 4.22 m | 41.7 cm | 47% / 53% | 1.67% |
| 5.00 m (16.4 ft) | 4.69 m | 5.35 m | 65.4 cm | 47% / 53% | 1.33% |
| 7.00 m (23.0 ft) | 6.41 m | 7.70 m | 1.29 m | 45% / 55% | 0.95% |
| 10.0 m (32.8 ft) | 8.84 m | 11.5 m | 2.66 m | 43% / 57% | 0.66% |
| 15.0 m (49.2 ft) | 12.5 m | 18.7 m | 6.13 m | 40% / 60% | 0.44% |
| 20.0 m (65.6 ft) | 15.8 m | 27.1 m | 11.3 m | 37% / 63% | 0.33% |
| 30.0 m (98.4 ft) | 21.5 m | 49.4 m | 27.9 m | 30% / 70% | 0.22% |
| 50.0 m (164 ft) | 30.2 m | 145 m | 115 m | 17% / 83% | 0.13% |
| 100 m (328 ft) | 43.3 m | ∞ | ∞ | — | 0.07% |
Try other settings#
40 mm at other apertures (subject at 3 m)#
Other focal lengths at f/1.4#
Same lens settings on other formats#
When to use it#
At f/1.4, a 40 mm lens on Micro Four Thirds is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 23.3 cm of sharp zone; for maximum front-to-back sharpness focus at 76.2 m and everything from 38.1 m to infinity will be acceptably sharp.
See also the f/1.4 aperture guide.
Frequently asked questions#
What is the depth of field of a 40mm lens at f/1.4?
On Micro Four Thirds, focused at 3 m, it is 23.3 cm; at 1 m it is 2.5 cm.
What is the hyperfocal distance for 40mm f/1.4?
76.2 m (250 ft) on Micro Four Thirds. Everything from 38.1 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources