f/45
Aperture
11.0
Stops less light than f/1
0.05%
Light vs f/1
∞
DoF: 50 mm at 3 m (FF)
60.4 µm
Airy disk diameter
Depth of field at f/45 (full frame)#
| Focal | at 1 m | at 2 m | at 5 m | at 10 m | Hyperfocal |
|---|---|---|---|---|---|
| 16 mm | ∞ | ∞ | ∞ | ∞ | 20.6 cm |
| 24 mm | ∞ | ∞ | ∞ | ∞ | 45.1 cm |
| 35 mm | ∞ | ∞ | ∞ | ∞ | 94.2 cm |
| 50 mm | 1.39 m | ∞ | ∞ | ∞ | 1.90 m |
| 85 mm | 35.2 cm | 1.64 m | 58.6 m | ∞ | 5.44 m |
| 135 mm | 12.9 cm | 56.3 cm | 4.14 m | 31.4 m | 13.6 m |
| 200 mm | 5.4 cm | 24.4 cm | 1.66 m | 7.43 m | 29.8 m |
Diffraction at f/45#
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 | 10.1× | diffraction-limited |
| Full frame 45 MP | 4.39 µm | 13.7× | diffraction-limited |
| Full frame 61 MP | 3.79 µm | 15.9× | diffraction-limited |
| APS-C 24 MP | 3.92 µm | 15.4× | diffraction-limited |
| APS-C 40 MP | 3.04 µm | 19.9× | diffraction-limited |
| Micro Four Thirds 20 MP | 3.34 µm | 18.1× | diffraction-limited |
| 1-inch 20 MP | 2.41 µm | 25.0× | diffraction-limited |
| Smartphone 1/1.3" 50 MP | 1.17 µm | 51.5× | diffraction-limited |
f/45 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/67.5 |
| Canon APS-C (1.6×) | f/72.0 |
| Micro Four Thirds (2×) | f/90.0 |
| 1-inch (2.7×) | f/121.5 |
Shutter speed at f/45#
| Light | ISO 100 | ISO 400 | ISO 1600 | ISO 6400 |
|---|---|---|---|---|
| EV 15 · Bright sun, distinct shadows (Sunny 16) | 1/15 s | 1/60 s | 1/250 s | 1/1000 s |
| EV 13 · Cloudy-bright, no shadows | 1/4 s | 1/15 s | 1/60 s | 1/250 s |
| EV 12 · Heavy overcast / open shade | 0.5 s | 1/8 s | 1/30 s | 1/125 s |
| EV 10 · Just after sunset | 2 s | 0.5 s | 1/8 s | 1/30 s |
| EV 8 · Bright interior, city street at night | 8 s | 2 s | 0.5 s | 1/8 s |
| EV 5 · Home interior at night | 1 min | 15 s | 4 s | 1 s |
| EV 2 · Distant city lights | > 4 min | 2 min | 30 s | 8 s |
| EV -2 · Moonlit landscape | > 4 min | > 4 min | > 4 min | 2 min |
When to use f/45#
f/45 is a go-to setting for maximum depth of field (macro, focus-free landscapes) and long exposures in daylight, at the cost of diffraction softness.
Other apertures#
Frequently asked questions#
Is f/45 a wide aperture?
No — f/45 is a small (narrow) aperture. Smaller numbers mean larger openings.
How much light does f/45 let in compared to f/2.8?
0.00× (-8.0 stops).
Last updated October 03, 2026 · How we calculate · Sources