44.5 m
Hyperfocal distance
22.2 m
Sharp from (focused at hyperfocal)
61 mm f/2.8
Full-frame equivalent
39°
Diagonal angle of view
Depth of field by subject distance#
40 mm at f/1.8 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) | 29.8 cm | 30.2 cm | 0.4 cm | 50% / 50% | 14.55% |
| 50.0 cm (1.64 ft) | 49.5 cm | 50.5 cm | 1.0 cm | 49% / 51% | 8.22% |
| 75.0 cm (2.46 ft) | 73.8 cm | 76.2 cm | 2.4 cm | 49% / 51% | 5.33% |
| 1.00 m (3.28 ft) | 97.9 cm | 1.02 m | 4.3 cm | 49% / 51% | 3.94% |
| 1.50 m (4.92 ft) | 1.45 m | 1.55 m | 9.9 cm | 48% / 52% | 2.59% |
| 2.00 m (6.56 ft) | 1.92 m | 2.09 m | 17.7 cm | 48% / 52% | 1.93% |
| 3.00 m (9.84 ft) | 2.81 m | 3.21 m | 40.1 cm | 47% / 53% | 1.28% |
| 4.00 m (13.1 ft) | 3.67 m | 4.39 m | 71.9 cm | 46% / 54% | 0.96% |
| 5.00 m (16.4 ft) | 4.50 m | 5.63 m | 1.13 m | 44% / 56% | 0.76% |
| 7.00 m (23.0 ft) | 6.05 m | 8.30 m | 2.25 m | 42% / 58% | 0.54% |
| 10.0 m (32.8 ft) | 8.17 m | 12.9 m | 4.72 m | 39% / 61% | 0.38% |
| 15.0 m (49.2 ft) | 11.2 m | 22.6 m | 11.4 m | 33% / 67% | 0.25% |
| 20.0 m (65.6 ft) | 13.8 m | 36.3 m | 22.5 m | 28% / 72% | 0.19% |
| 30.0 m (98.4 ft) | 17.9 m | 92.1 m | 74.1 m | 16% / 84% | 0.13% |
| 50.0 m (164 ft) | 23.5 m | ∞ | ∞ | — | 0.08% |
| 100 m (328 ft) | 30.8 m | ∞ | ∞ | — | 0.04% |
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 APS-C is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 40.1 cm of sharp zone; for maximum front-to-back sharpness focus at 44.5 m and everything from 22.2 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 APS-C, focused at 3 m, it is 40.1 cm; at 1 m it is 4.3 cm.
What is the hyperfocal distance for 40mm f/1.8?
44.5 m (146 ft) on APS-C. Everything from 22.2 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources