1.3 km
Hyperfocal distance
667 m
Sharp from (focused at hyperfocal)
400 mm f/4.0
Full-frame equivalent
6°
Diagonal angle of view
Depth of field by subject distance#
400 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 |
|---|---|---|---|---|---|
| 1.00 m (3.28 ft) | 100.0 cm | 1.00 m | 0.1 cm | 50% / 50% | 185.19% |
| 1.50 m (4.92 ft) | 1.50 m | 1.50 m | 0.2 cm | 50% / 50% | 101.01% |
| 2.00 m (6.56 ft) | 2.00 m | 2.00 m | 0.5 cm | 50% / 50% | 69.44% |
| 3.00 m (9.84 ft) | 2.99 m | 3.01 m | 1.2 cm | 50% / 50% | 42.74% |
| 4.00 m (13.1 ft) | 3.99 m | 4.01 m | 2.2 cm | 50% / 50% | 30.86% |
| 5.00 m (16.4 ft) | 4.98 m | 5.02 m | 3.5 cm | 50% / 50% | 24.15% |
| 7.00 m (23.0 ft) | 6.97 m | 7.03 m | 6.9 cm | 50% / 50% | 16.84% |
| 10.0 m (32.8 ft) | 9.93 m | 10.1 m | 14.4 cm | 50% / 50% | 11.57% |
| 15.0 m (49.2 ft) | 14.8 m | 15.2 m | 32.9 cm | 49% / 51% | 7.61% |
| 20.0 m (65.6 ft) | 19.7 m | 20.3 m | 58.8 cm | 49% / 51% | 5.67% |
| 30.0 m (98.4 ft) | 29.3 m | 30.7 m | 1.33 m | 49% / 51% | 3.75% |
| 50.0 m (164 ft) | 48.2 m | 51.9 m | 3.73 m | 48% / 52% | 2.24% |
| 100 m (328 ft) | 93.0 m | 108 m | 15.0 m | 46% / 54% | 1.12% |
Try other settings#
Near limit—
Far limit—
Depth of field—
Hyperfocal distance—
In front / behind—
400 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 400 mm lens on full frame is a natural choice for general photography. Focused at 3 m you get 1.2 cm of sharp zone; for maximum front-to-back sharpness focus at 1.3 km and everything from 667 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 400mm lens at f/4?
On full frame, focused at 3 m, it is 1.2 cm; at 1 m it is 0.1 cm.
What is the hyperfocal distance for 400mm f/4?
1.3 km (4376 ft) on full frame. Everything from 667 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources