28.6 m
Hyperfocal distance
14.3 m
Sharp from (focused at hyperfocal)
61 mm f/4.3
Full-frame equivalent
39°
Diagonal angle of view
Depth of field by subject distance#
40 mm at f/2.8 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) | 29.7 cm | 30.3 cm | 0.5 cm | 50% / 50% | 9.35% |
| 50.0 cm (1.64 ft) | 49.2 cm | 50.8 cm | 1.6 cm | 49% / 51% | 5.29% |
| 75.0 cm (2.46 ft) | 73.2 cm | 76.9 cm | 3.7 cm | 49% / 51% | 3.42% |
| 1.00 m (3.28 ft) | 96.7 cm | 1.03 m | 6.7 cm | 48% / 52% | 2.53% |
| 1.50 m (4.92 ft) | 1.43 m | 1.58 m | 15.4 cm | 47% / 53% | 1.67% |
| 2.00 m (6.56 ft) | 1.87 m | 2.15 m | 27.6 cm | 47% / 53% | 1.24% |
| 3.00 m (9.84 ft) | 2.72 m | 3.35 m | 62.8 cm | 45% / 55% | 0.82% |
| 4.00 m (13.1 ft) | 3.51 m | 4.64 m | 1.13 m | 43% / 57% | 0.61% |
| 5.00 m (16.4 ft) | 4.26 m | 6.05 m | 1.79 m | 41% / 59% | 0.49% |
| 7.00 m (23.0 ft) | 5.63 m | 9.25 m | 3.63 m | 38% / 62% | 0.35% |
| 10.0 m (32.8 ft) | 7.42 m | 15.4 m | 7.94 m | 33% / 67% | 0.24% |
| 15.0 m (49.2 ft) | 9.85 m | 31.5 m | 21.6 m | 24% / 76% | 0.16% |
| 20.0 m (65.6 ft) | 11.8 m | 66.4 m | 54.6 m | 15% / 85% | 0.12% |
| 30.0 m (98.4 ft) | 14.6 m | ∞ | ∞ | — | 0.08% |
| 50.0 m (164 ft) | 18.2 m | ∞ | ∞ | — | 0.05% |
| 100 m (328 ft) | 22.2 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/2.8#
Same lens settings on other formats#
When to use it#
At f/2.8, a 40 mm lens on APS-C is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 62.8 cm of sharp zone; for maximum front-to-back sharpness focus at 28.6 m and everything from 14.3 m to infinity will be acceptably sharp.
See also the f/2.8 aperture guide.
Frequently asked questions#
What is the depth of field of a 40mm lens at f/2.8?
On APS-C, focused at 3 m, it is 62.8 cm; at 1 m it is 6.7 cm.
What is the hyperfocal distance for 40mm f/2.8?
28.6 m (93.9 ft) on APS-C. Everything from 14.3 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources