7.43 m
Hyperfocal distance
3.71 m
Sharp from (focused at hyperfocal)
20 mm f/1.8
Full-frame equivalent
94°
Diagonal angle of view
Depth of field by subject distance#
20 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) | 28.9 cm | 31.2 cm | 2.3 cm | 48% / 52% | 2.20% |
| 50.0 cm (1.64 ft) | 47.0 cm | 53.5 cm | 6.5 cm | 47% / 53% | 1.29% |
| 75.0 cm (2.46 ft) | 68.3 cm | 83.2 cm | 14.9 cm | 45% / 55% | 0.85% |
| 1.00 m (3.28 ft) | 88.3 cm | 1.15 m | 26.9 cm | 43% / 57% | 0.63% |
| 1.50 m (4.92 ft) | 1.25 m | 1.87 m | 62.4 cm | 40% / 60% | 0.42% |
| 2.00 m (6.56 ft) | 1.58 m | 2.73 m | 1.15 m | 37% / 63% | 0.31% |
| 3.00 m (9.84 ft) | 2.14 m | 5.02 m | 2.88 m | 30% / 70% | 0.21% |
| 4.00 m (13.1 ft) | 2.60 m | 8.64 m | 6.04 m | 23% / 77% | 0.16% |
| 5.00 m (16.4 ft) | 2.99 m | 15.3 m | 12.3 m | 16% / 84% | 0.12% |
| 7.00 m (23.0 ft) | 3.60 m | 121 m | 118 m | 3% / 97% | 0.09% |
| 10.0 m (32.8 ft) | 4.26 m | ∞ | ∞ | — | 0.06% |
| 15.0 m (49.2 ft) | 4.96 m | ∞ | ∞ | — | 0.04% |
| 20.0 m (65.6 ft) | 5.41 m | ∞ | ∞ | — | 0.03% |
| 30.0 m (98.4 ft) | 5.94 m | ∞ | ∞ | — | 0.02% |
| 50.0 m (164 ft) | 6.45 m | ∞ | ∞ | — | 0.01% |
| 100 m (328 ft) | 6.90 m | ∞ | ∞ | — | 0.01% |
Try other settings#
Near limit—
Far limit—
Depth of field—
Hyperfocal distance—
In front / behind—
20 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 20 mm lens on full frame is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 2.88 m of sharp zone; for maximum front-to-back sharpness focus at 7.43 m and everything from 3.71 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 20mm lens at f/1.8?
On full frame, focused at 3 m, it is 2.88 m; at 1 m it is 26.9 cm.
What is the hyperfocal distance for 20mm f/1.8?
7.43 m (24.4 ft) on full frame. Everything from 3.71 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources