ISO SETTINGS
ISO Modes | ISO Chart | ISO Time of Day
ISO in digital photography refers to the sensitivity of the CCD to light. Sensitivity is rated in ISO. A low ISO is less sensitive to light and needs more light to create an exposure. A higher ISO needs less light. However, with higher ISO you may get graininess in your images.
Auto ISO mode
All consumer digital cameras have an Auto ISO mode. The camera automatically selects the sensitivity, known as ISO, according to the level of light in a scene. The user has no control over which ISO number is used.
In bright light a lower ISO will be selected. In low light an higher ISO number will be selected.
Auto High ISO Mode
Some digital cameras have an Auto High ISO mode, which is primarily used in very low and difficult lighting. The camera selects ISO number higher than Auto ISO mode, usually ISO 400 and above.
Higher ISO means faster shutter speeds
When a higher ISO is selected, shutter speeds are faster. Use of faster shutter speeds helps prevent blurred images due to camera shake. Using high ISO numbers also allows you to turn off the flash when shooting in dark areas.
Higher ISO means more image "noise"
Keep in mind that the higher ISO, the more noise will appear in images. That's why many photographers, in order to prevent noise, prefer to set ISO manually and select low ISO numbers even if they must use a tripod to prevent camera shake. Still, an photo with noise is better than no photo at all.
Image noise will be higher when using Auto High ISO mode than using Auto ISO mode.
Light Sesnitivity ISO and shutter Speeds
When lighting is poor, fast shutter speeds are not available, (you underexpose your image). To expose the images at faster shutter speeds, make your camera more sensitive to the light (ISO). Most cameras ISO range from 50, 100, 200, 400, 800, and 1600. The interval between ISO settings is 1 Stop (term used to describe the intervals in apeture and shutter speeds).
If you increase your ISO from 100 to 400 you are increasing sensitity to light by 2 stops, which allows you to use faster shutter speeds. If you were to go into a church, and the do not want to use your flash, you could turn up your ISO to 800 to take photos at higher shutter speeds. The opposite can also apply. in that same church, set up your tri-pod and adjust for a low ISO, (100) you would need to set your shutter speed to a long 2-3 second exposure.
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ISO 1600, with no flash |
| Light Requirements | Benefits/Drawbacks | Photographic Uses | |
| Low ISO (64 or 100) | Requires more light to create exposure. Shutter speeds may be longer. | Creates detailed images with little grain. | Indoor Shooting |
| Medium ISO (200 - 400) | Good for variable or unpredictable lighting conditions | Grains are not too noticeable | General Purpose |
| High ISO (800 or higher) | Requires less light to create the same exposure so shutter speeds are faster | Grains may result in less-detailed "noisy" exposure | Low Light |
| Early morning, use ISO 100-400; |  |
| Mid-day sun, use ISO 100-200; | |
| Late afternoon tosunset, use ISO 400; | |
| Evenings, use ISO 400-1600. | |