29.7 m
Hyperfocal distance
14.8 m
Sharp from (focused at hyperfocal)
40 mm f/1.8
Full-frame equivalent
57°
Diagonal angle of view
Depth of field by subject distance#
40 mm at f/1.8 on full frame (36×24 mm), circle of confusion 30 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) | 29.7 cm | 30.3 cm | 0.5 cm | 50% / 50% | 9.50% |
| 50.0 cm (1.64 ft) | 49.2 cm | 50.8 cm | 1.6 cm | 49% / 51% | 5.37% |
| 75.0 cm (2.46 ft) | 73.2 cm | 76.8 cm | 3.6 cm | 49% / 51% | 3.48% |
| 1.00 m (3.28 ft) | 96.9 cm | 1.03 m | 6.5 cm | 48% / 52% | 2.57% |
| 1.50 m (4.92 ft) | 1.43 m | 1.58 m | 14.8 cm | 48% / 52% | 1.69% |
| 2.00 m (6.56 ft) | 1.88 m | 2.14 m | 26.6 cm | 47% / 53% | 1.26% |
| 3.00 m (9.84 ft) | 2.73 m | 3.33 m | 60.5 cm | 45% / 55% | 0.83% |
| 4.00 m (13.1 ft) | 3.53 m | 4.62 m | 1.09 m | 43% / 57% | 0.62% |
| 5.00 m (16.4 ft) | 4.28 m | 6.01 m | 1.72 m | 42% / 58% | 0.50% |
| 7.00 m (23.0 ft) | 5.67 m | 9.15 m | 3.48 m | 38% / 62% | 0.35% |
| 10.0 m (32.8 ft) | 7.48 m | 15.1 m | 7.58 m | 33% / 67% | 0.25% |
| 15.0 m (49.2 ft) | 9.97 m | 30.3 m | 20.3 m | 25% / 75% | 0.17% |
| 20.0 m (65.6 ft) | 11.9 m | 61.3 m | 49.3 m | 16% / 84% | 0.12% |
| 30.0 m (98.4 ft) | 14.9 m | ∞ | ∞ | — | 0.08% |
| 50.0 m (164 ft) | 18.6 m | ∞ | ∞ | — | 0.05% |
| 100 m (328 ft) | 22.9 m | ∞ | ∞ | — | 0.02% |
Try other settings#
Near limit—
Far limit—
Depth of field—
Hyperfocal distance—
In front / behind—
40 mm at other apertures (subject at 3 m)#
Other focal lengths at f/1.8#
Same lens settings on other formats#
When to use it#
At f/1.8, a 40 mm lens on full frame is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 60.5 cm of sharp zone; for maximum front-to-back sharpness focus at 29.7 m and everything from 14.8 m to infinity will be acceptably sharp.
See also the f/1.8 aperture guide.
Frequently asked questions#
What is the depth of field of a 40mm lens at f/1.8?
On full frame, focused at 3 m, it is 60.5 cm; at 1 m it is 6.5 cm.
What is the hyperfocal distance for 40mm f/1.8?
29.7 m (97.3 ft) on full frame. Everything from 14.8 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources