Camera Modes

High sensitivity mode

Written by Gail Bjork

When a digital camera is set to High ISO mode, it automatically adjusts the camera to a high ISO number when light is low. This is not always a good thing.

Shooting at higher ISO numbers allows more light to enter the camera. In low light, high ISO helps reduce the effect of camera shake, which causes images to blur. It also allows photos to be taken without a flash, making photos appear more natural.

However, unlike digital single lens reflex cameras, most compact digital cameras have small sensors so image quality starts to degrade when sensitivity is set above ISO 100. The higher the ISO, the more noise is introduced in images.

Pitfalls of using high sensitivity mode

Shoot at a very high ISO number and image quality will degrade. The camera may also automatically reduce the image resolution. Click image for detail

Click image to better see the effects of very high ISO and image resizing.

If your camera has a High Sensitivity Mode, use it cautiously! The mode automatically selects a very high ISO number according to the level of light in a scene: ISO 800, 1600, 3200 and above!

When set to very high ISO, a digital camera may automatically reduce the size, or resolution, of  images. The reason the camera reduces the resolution is because noise is usually less visible when an image is reduced in size.

High ISO photos may not print well, since image detail is smeared due to noise. Depending on the degree of noise, it may not show in a 4X6″ print. But noise becomes readily apparent in large prints.

Noise reduction and high ISO

Digital cameras address noise with built-in noise reduction (NR). However, noise reduction can cause images to look soft. Loss of fine detail and smearing of colors occurs in the original image. The higher the ISO, the more noise reduction is used resulting in greater smearing and loss of detail. The detail is rarely recovered when editing.

Bottom line about using high ISO

Avoid using very high ISO number unless you have a digital camera that is capable of handling it well. For important low light shots, consider shooting at a lower ISO number and using a camera support such as a tripod.

Remember though, getting a shot, even at reduced size and image quality, is often more important than not getting the shot at all. So if there are no other options, shoot at  high ISO numbers.

About the author

Gail Bjork

Gail Bjork, who is passionate about digital photography, is the owner and editor of Digicamhelp.Gail is the author of three illustrated ebooks about digital photography. A number of her photos and digital photography related articles appear at other websites.In 2006, a series of her photos, People in the Louvre, were exhibited at the Underground Photo Gallery
in Iisalmi Finland. Eight of her photos taken in the Florida scrub are on permanent exhibition at Parrish Medical Center in Titusville, Florida.Gail served twelve years as an elected member of The School Board of Palm Beach County, Florida, one of the largest school districts in the U.S. She has also been the editor of a small town newspaper and a free-lance writer. Gail and her husband owned and ran several small businesses.