ISO makes a night-and-day difference in the quality of your photos.
ISO is only three letters, but this tiny acronym represents one of the most crucial features of photography. Standing for International Organization for Standardization,this term refers to a range of numbers, usually from 100 to 1600, that indicate your camera sensor's sensitivity to light. Although many digital cameras automatically adjust ISO for you, understanding and learning to use this valuable tool enables you to capture high-quality photos in almost any lighting conditions.
Lighting
Generally, a low ISO indicates a low sensitivity to light and the higher the ISO, the higher the sensitivity to light.. An ISO setting of 100 to 200 is good to use on a bright day. When light is moderate but flash would ruin the photo, such as at sunrise or sunset, increase ISO to 400 t0 800. For photos with very little, use one of the highest ISO settings to make the most of the available light.
Grain
As you increase ISO, more 'noise' or 'grain' will appear in your photo. This can add interesting effects to photos, but generally it's unwanted. Typically found in photos when an ISO is increased to 400 or higher, grain occurs when there is not enough light to optimally illuminate the photo subject, resulting in an image with reduced sharpness and clarity. To adjust for this, use the lowest ISO setting necessary for a good quality picture. For example, in an aquarium, there is enough light so your ISO does not have to be on the absolute highest setting for a clear photo.
Movement
In addition to lighting, speed and movement of your subjects are important considerations when selecting ISO settings. A higher ISO allows you to capture well-exposed photos of moving subjects in less-than-ideal lighting conditions. Poor lighting makes it difficult to capture movement, often producing blurry pictures because the camera slows shutter speed to let in as much light as possible. Increasing ISO allows you to capture movement, resulting in faster shutter speeds because with increased sensitivity to light, exposure takes less time. When photographing moving subjects, increase ISO one setting at a time until a desirable balance of movement and exposure is captured.
Tripod
If your subjects are stationary, feel free to use whichever ISO setting you prefer. However, use a tripod whenever possible if your location requires a moderate ISO. In places such as cathedrals or museums where flash is not allowed and light is low, a tripod allows you to use higher ISO to avoid blurry pictures. If a tripod is not available, hold your camera absolutely still for three seconds after it clicks and takes the picture.
Tags: sensitivity light, allows capture, blurry pictures, capture movement, enough light, lighting conditions, moving subjects