f/1
Aperture
0.0
Stops less light than f/1
100%
Light vs f/1
21.3 cm
DoF: 50 mm at 3 m (FF)
1.3 µm
Airy disk diameter
Depth of field at f/1 (full frame)#
| Focal | at 1 m | at 2 m | at 5 m | at 10 m | Hyperfocal |
|---|---|---|---|---|---|
| 16 mm | 23.4 cm | 98.3 cm | 8.86 m | ∞ | 8.55 m |
| 24 mm | 10.2 cm | 41.6 cm | 2.78 m | 14.2 m | 19.2 m |
| 35 mm | 4.7 cm | 19.3 cm | 1.23 m | 5.19 m | 40.9 m |
| 50 mm | 2.3 cm | 9.4 cm | 59.6 cm | 2.42 m | 83.4 m |
| 85 mm | 0.8 cm | 3.2 cm | 20.4 cm | 82.5 cm | 241 m |
| 135 mm | 0.3 cm | 1.2 cm | 8.0 cm | 32.5 cm | 608 m |
| 200 mm | 0.1 cm | 0.5 cm | 3.6 cm | 14.7 cm | 1.3 km |
Diffraction at f/1#
Diffraction softening becomes visible at 100% once the Airy disk spans more than about two pixels. It is a gradual effect, not a cliff.
| Sensor | Pixel pitch | Airy disk / pixel | Pixel-level sharpness |
|---|---|---|---|
| Full frame 24 MP | 6.00 µm | 0.2× | no visible loss |
| Full frame 45 MP | 4.39 µm | 0.3× | no visible loss |
| Full frame 61 MP | 3.79 µm | 0.4× | no visible loss |
| APS-C 24 MP | 3.92 µm | 0.3× | no visible loss |
| APS-C 40 MP | 3.04 µm | 0.4× | no visible loss |
| Micro Four Thirds 20 MP | 3.34 µm | 0.4× | no visible loss |
| 1-inch 20 MP | 2.41 µm | 0.6× | no visible loss |
| Smartphone 1/1.3" 50 MP | 1.17 µm | 1.1× | no visible loss |
f/1 on smaller sensors equals…#
Exposure (brightness) is the same at a given f-number on every format; equivalence describes depth of field and total light.
| Used on | Full-frame equivalent depth of field |
|---|---|
| APS-C (1.5×) | f/1.5 |
| Canon APS-C (1.6×) | f/1.6 |
| Micro Four Thirds (2×) | f/2.0 |
| 1-inch (2.7×) | f/2.7 |
Shutter speed at f/1#
| Light | ISO 100 | ISO 400 | ISO 1600 | ISO 6400 |
|---|---|---|---|---|
| EV 15 · Bright sun, distinct shadows (Sunny 16) | too bright | too bright | too bright | too bright |
| EV 13 · Cloudy-bright, no shadows | 1/8000 s | too bright | too bright | too bright |
| EV 12 · Heavy overcast / open shade | 1/4000 s | too bright | too bright | too bright |
| EV 10 · Just after sunset | 1/1000 s | 1/4000 s | too bright | too bright |
| EV 8 · Bright interior, city street at night | 1/250 s | 1/1000 s | 1/4000 s | too bright |
| EV 5 · Home interior at night | 1/30 s | 1/125 s | 1/500 s | 1/2000 s |
| EV 2 · Distant city lights | 1/4 s | 1/15 s | 1/60 s | 1/250 s |
| EV -2 · Moonlit landscape | 4 s | 1 s | 1/4 s | 1/15 s |
When to use f/1#
f/1 is a go-to setting for low light, shallow depth of field, creamy bokeh and subject isolation — the classic portrait and night-street aperture.
Other apertures#
Frequently asked questions#
Is f/1 a wide aperture?
Yes — f/1 is a wide (fast) aperture that lets in lots of light. Smaller numbers mean larger openings.
How much light does f/1 let in compared to f/2.8?
7.84× (+3.0 stops).
Last updated October 03, 2026 · How we calculate · Sources