57.2 m
Hyperfocal distance
28.6 m
Sharp from (focused at hyperfocal)
61 mm f/2.1
Full-frame equivalent
39°
Diagonal angle of view
Depth of field by subject distance#
40 mm at f/1.4 on APS-C (23.5×15.6 mm), circle of confusion 20 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 | 0.3 cm | 50% / 50% | 18.70% |
| 50.0 cm (1.64 ft) | 49.6 cm | 50.4 cm | 0.8 cm | 50% / 50% | 10.57% |
| 75.0 cm (2.46 ft) | 74.1 cm | 75.9 cm | 1.9 cm | 49% / 51% | 6.85% |
| 1.00 m (3.28 ft) | 98.3 cm | 1.02 m | 3.4 cm | 49% / 51% | 5.07% |
| 1.50 m (4.92 ft) | 1.46 m | 1.54 m | 7.7 cm | 49% / 51% | 3.33% |
| 2.00 m (6.56 ft) | 1.93 m | 2.07 m | 13.7 cm | 48% / 52% | 2.48% |
| 3.00 m (9.84 ft) | 2.85 m | 3.16 m | 31.2 cm | 47% / 53% | 1.64% |
| 4.00 m (13.1 ft) | 3.74 m | 4.30 m | 55.7 cm | 47% / 53% | 1.23% |
| 5.00 m (16.4 ft) | 4.60 m | 5.48 m | 87.5 cm | 46% / 54% | 0.98% |
| 7.00 m (23.0 ft) | 6.24 m | 7.97 m | 1.73 m | 44% / 56% | 0.70% |
| 10.0 m (32.8 ft) | 8.52 m | 12.1 m | 3.60 m | 41% / 59% | 0.49% |
| 15.0 m (49.2 ft) | 11.9 m | 20.3 m | 8.43 m | 37% / 63% | 0.33% |
| 20.0 m (65.6 ft) | 14.8 m | 30.7 m | 15.9 m | 33% / 67% | 0.24% |
| 30.0 m (98.4 ft) | 19.7 m | 63.1 m | 43.4 m | 24% / 76% | 0.16% |
| 50.0 m (164 ft) | 26.7 m | 398 m | 371 m | 6% / 94% | 0.10% |
| 100 m (328 ft) | 36.4 m | ∞ | ∞ | — | 0.05% |
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/1.4#
Same lens settings on other formats#
When to use it#
At f/1.4, a 40 mm lens on APS-C is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 31.2 cm of sharp zone; for maximum front-to-back sharpness focus at 57.2 m and everything from 28.6 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 APS-C, focused at 3 m, it is 31.2 cm; at 1 m it is 3.4 cm.
What is the hyperfocal distance for 40mm f/1.4?
57.2 m (188 ft) on APS-C. Everything from 28.6 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources