ISO sets how sensitive the sensor is to light. Higher numbers brighten the image but add visible noise, so the goal is the lowest value that still gives a sharp, well-lit picture. These ranges are general; your camera’s behavior may differ, so check the maker’s guide.
Ranges by Lighting
| Lighting | General ISO range | Note |
|---|---|---|
| Bright sun | 100 to 200 | Plenty of light, keep it clean |
| Light cloud or open shade | 200 to 400 | Slightly less light |
| Heavy overcast, golden hour | 400 to 800 | Softer, lower light |
| Bright indoors, near windows | 400 to 1600 | Depends on lens aperture |
| Ordinary room lighting | 800 to 3200 | Often needs a wide aperture |
| Sports halls, stage events | 1600 to 6400 | Fast shutter needs lots of light |
| Night, handheld | 3200 and above | Noise is more visible |
| Night, on a tripod | 100 to 800 | Use longer exposures instead |
Never look at the sun through a camera or lens, even when shooting at golden hour.
Working Out Your ISO
- Set the aperture you want for the look of the picture.
- Set the shutter speed you need for sharpness.
- Raise ISO until the exposure looks right.
- If noise is too strong, see if you can slow the shutter or open the aperture, or add light.
Managing Noise
- Expose well: underexposed pictures lifted later show more noise.
- Shoot raw when possible, for better noise reduction in editing.
- Larger sensors usually handle high ISO more cleanly.
- Noise reduction tools can help but may soften detail.
Auto ISO
Many cameras let you set a maximum and a minimum shutter speed for auto ISO. It is useful when light changes quickly, such as at events or while walking. Set a ceiling you are happy with, then watch the results.
Test your own camera. Photograph the same dim scene at several ISO values, then view the files at full size on a computer. Note the value at which noise begins to bother you for the sizes you print or share. That personal limit is more useful than any general table, and it will differ between camera models.
Remember that noise is more visible in dark, smooth areas such as skies and shadows than in busy, detailed ones, so a scene with texture hides it better.
Some cameras offer extended low and high values beyond the normal range. These can be handy in a pinch, but they often trade away dynamic range or add more noise, so use them sparingly and check the maker’s guide.
FAQ
Is high ISO always bad?
No. A grainy but sharp picture is usually better than a clean but blurry one.
Does base ISO matter?
Yes. The lowest native value often gives the cleanest result and the best tonal range.
The Short Version
Use low ISO in bright light and raise it only as conditions require. Set aperture and shutter speed first, then let ISO make up the difference.