1.9 km
Hyperfocal distance
953 m
Sharp from (focused at hyperfocal)
400 mm f/2.8
Full-frame equivalent
6°
Diagonal angle of view
Depth of field by subject distance#
400 mm at f/2.8 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 |
|---|---|---|---|---|---|
| 1.00 m (3.28 ft) | 100.0 cm | 1.00 m | 0.1 cm | 50% / 50% | 264.55% |
| 1.50 m (4.92 ft) | 1.50 m | 1.50 m | 0.2 cm | 50% / 50% | 144.30% |
| 2.00 m (6.56 ft) | 2.00 m | 2.00 m | 0.3 cm | 50% / 50% | 99.21% |
| 3.00 m (9.84 ft) | 3.00 m | 3.00 m | 0.8 cm | 50% / 50% | 61.05% |
| 4.00 m (13.1 ft) | 3.99 m | 4.01 m | 1.5 cm | 50% / 50% | 44.09% |
| 5.00 m (16.4 ft) | 4.99 m | 5.01 m | 2.4 cm | 50% / 50% | 34.51% |
| 7.00 m (23.0 ft) | 6.98 m | 7.02 m | 4.9 cm | 50% / 50% | 24.05% |
| 10.0 m (32.8 ft) | 9.95 m | 10.1 m | 10.1 cm | 50% / 50% | 16.53% |
| 15.0 m (49.2 ft) | 14.9 m | 15.1 m | 23.0 cm | 50% / 50% | 10.87% |
| 20.0 m (65.6 ft) | 19.8 m | 20.2 m | 41.2 cm | 49% / 51% | 8.10% |
| 30.0 m (98.4 ft) | 29.5 m | 30.5 m | 93.3 cm | 49% / 51% | 5.36% |
| 50.0 m (164 ft) | 48.7 m | 51.3 m | 2.61 m | 49% / 51% | 3.20% |
| 100 m (328 ft) | 95.0 m | 106 m | 10.5 m | 47% / 53% | 1.59% |
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/2.8#
Same lens settings on other formats#
When to use it#
At f/2.8, a 400 mm lens on full frame is a natural choice for portraits and subject isolation. Focused at 3 m you get 0.8 cm of sharp zone; for maximum front-to-back sharpness focus at 1.9 km and everything from 953 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 400mm lens at f/2.8?
On full frame, focused at 3 m, it is 0.8 cm; at 1 m it is 0.1 cm.
What is the hyperfocal distance for 400mm f/2.8?
1.9 km (6251 ft) on full frame. Everything from 953 m to infinity is acceptably sharp.
Last updated October 03, 2026 · How we calculate · Sources