ISO 100
Sensitivity
+0.0
Stops vs ISO 100
1.00×
Brightness gain vs ISO 100
ISO 100 in practice: Base or near-base ISO: maximum dynamic range and clean files.
Shutter speeds at ISO 100#
| Light | f/1.4 | f/2.8 | f/5.6 | f/8 |
|---|---|---|---|---|
| EV 15 · Bright sun, distinct shadows (Sunny 16) | too bright | 1/4000 s | 1/1000 s | 1/500 s |
| EV 12 · Heavy overcast / open shade | 1/2000 s | 1/500 s | 1/125 s | 1/60 s |
| EV 10 · Just after sunset | 1/500 s | 1/125 s | 1/30 s | 1/15 s |
| EV 8 · Bright interior, city street at night | 1/125 s | 1/30 s | 1/8 s | 1/4 s |
| EV 6 · Home interior, daytime | 1/30 s | 1/8 s | 0.5 s | 1 s |
| EV 4 · Candle-lit close-up, Christmas lights | 1/8 s | 0.5 s | 2 s | 4 s |
| EV 2 · Distant city lights | 0.5 s | 2 s | 8 s | 15 s |
| EV 0 · Dim interior, Milky Way in moonlight | 2 s | 8 s | 30 s | 1 min |
| EV -2 · Moonlit landscape | 8 s | 30 s | 2 min | > 4 min |
| EV -4 · Aurora (bright) | 30 s | 2 min | > 4 min | > 4 min |
| EV -6 · Milky Way, starlight only | 2 min | > 4 min | > 4 min | > 4 min |
Same noise on other formats#
At the same framing and depth of field, a full-frame camera at this ISO produces similar noise to the smaller formats at the lower ISOs shown (equivalence theory).
| Full frame ISO 100 ≈ on | Equivalent ISO (same total light) |
|---|---|
| APS-C (1.5×) | ISO 44 |
| Micro Four Thirds (2×) | ISO 25 |
| 1-inch (2.7×) | ISO 14 |
| Medium format 44×33 (0.79×) | ISO 160 |
Exposure calculator#
Your metered (or known good) exposure
New settings — change aperture and/or ISO, we solve the shutter speed
Equivalent shutter speed—
Exposure value (EV₁₀₀)—
Light conditions—
Other ISO values#
Frequently asked questions#
Is ISO 100 high?
No — it is a low ISO. Base or near-base ISO: maximum dynamic range and clean files.
When should I use ISO 100?
When you need the shutter speed and aperture shown in the table above for your light level. Raise ISO only after you've reached the slowest safe shutter speed and widest useful aperture.
Last updated October 03, 2026 · How we calculate · Sources