3.35 m
Hyperfocal distance
1.68 m
Sharp from (focused at hyperfocal)
20 mm f/4.0
Full-frame equivalent
94°
Diagonal angle of view
Depth of field by subject distance#
20 mm at f/4 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) | 27.7 cm | 32.8 cm | 5.1 cm | 46% / 54% | 0.99% |
| 50.0 cm (1.64 ft) | 43.7 cm | 58.4 cm | 14.7 cm | 43% / 57% | 0.58% |
| 75.0 cm (2.46 ft) | 61.5 cm | 96.0 cm | 34.5 cm | 39% / 61% | 0.38% |
| 1.00 m (3.28 ft) | 77.3 cm | 1.42 m | 64.4 cm | 35% / 65% | 0.28% |
| 1.50 m (4.92 ft) | 1.04 m | 2.70 m | 1.66 m | 28% / 72% | 0.19% |
| 2.00 m (6.56 ft) | 1.25 m | 4.93 m | 3.67 m | 20% / 80% | 0.14% |
| 3.00 m (9.84 ft) | 1.58 m | 28.3 m | 26.7 m | 5% / 95% | 0.09% |
| 4.00 m (13.1 ft) | 1.82 m | ∞ | ∞ | — | 0.07% |
| 5.00 m (16.4 ft) | 2.00 m | ∞ | ∞ | — | 0.06% |
| 7.00 m (23.0 ft) | 2.26 m | ∞ | ∞ | — | 0.04% |
| 10.0 m (32.8 ft) | 2.50 m | ∞ | ∞ | — | 0.03% |
| 15.0 m (49.2 ft) | 2.73 m | ∞ | ∞ | — | 0.02% |
| 20.0 m (65.6 ft) | 2.86 m | ∞ | ∞ | — | 0.01% |
| 30.0 m (98.4 ft) | 3.00 m | ∞ | ∞ | — | 0.01% |
| 50.0 m (164 ft) | 3.13 m | ∞ | ∞ | — | 0.01% |
| 100 m (328 ft) | 3.23 m | ∞ | ∞ | — | 0.00% |
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/4#
| Focal length | Subject at | Total DoF |
|---|---|---|
| 14 mm | 3.00 m | ∞ |
| 16 mm | 3.00 m | ∞ |
| 20 mm | 3.00 m | 26.7 m |
| 24 mm | 3.00 m | 6.04 m |
| 28 mm | 3.00 m | 3.44 m |
| 35 mm | 3.00 m | 1.90 m |
| 40 mm | 3.00 m | 1.40 m |
| 50 mm | 3.00 m | 86.7 cm |
| 85 mm | 3.00 m | 29.1 cm |
| 105 mm | 3.00 m | 18.9 cm |
| 135 mm | 3.00 m | 11.3 cm |
| 200 mm | 10.0 m | 58.9 cm |
| 300 mm | 10.0 m | 25.9 cm |
| 400 mm | 10.0 m | 14.4 cm |
| 600 mm | 10.0 m | 6.3 cm |
Same lens settings on other formats#
When to use it#
At f/4, a 20 mm lens on full frame is a natural choice for general photography. Focused at 3 m you get 26.7 m of sharp zone; for maximum front-to-back sharpness focus at 3.35 m and everything from 1.68 m to infinity will be acceptably sharp.
See also the f/4 aperture guide.
Frequently asked questions#
What is the depth of field of a 20mm lens at f/4?
On full frame, focused at 3 m, it is 26.7 m; at 1 m it is 64.4 cm.
What is the hyperfocal distance for 20mm f/4?
3.35 m (11.0 ft) on full frame. Everything from 1.68 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources