How to Avoid Noise from Digital Zoom
For many photographers, understanding how to avoid noise from digital zoom can be quite a challenge. Digital zoom is a feature of many digital cameras which kicks in when the optical zoom has been fully extended. In contrast to optical zoom, which uses a physical lens to decrease apparent distance between photographer and subject, the digital zoom feature affects only the software side of digital photography. It enhances a portion of the image by blowing it up and adding pixels based on the digital zoom program's approximation of what should be in the photo. Due to the crudeness of this process, photographs taken with high digital zoom can have a grainy look caused by image noise.
Here are a few suggestion which should help you avoid this problem.
Method 1 - Shoot at a Low ISO
The ISO setting on your camera controls how sensitive it is to light. At a higher ISO, it will be easier to shoot in well-lit or outdoor environments. This also causes a camera at a high ISO to pick up more light than necessary. Avoid this by using your camera's intelligent ISO mode, (often denoted by an icon of a lower-case "i" within a rectangle) which selects the lowest reasonable ISO.
Method 2 - Quicker Shutter Speed
The longer your shutter is open, the more light will enter. If you digital camera has advanced settings, increase your shutter speed (that is, select a higher number, to effect a lower interval) to eliminate excess noise.
Method 3 - Shoot Well-Lit Photos
Noise will first appear in the darker areas of your image. If you must use digital zoom, use it only when there is an appropriate amount of light. Any more light than is necessary will cause noise, which can be partially negated by the first two methods, but any less light than is necessary will serve only to create a dark image. Often, using a photo editor to increase the lighting levels of a dark photograph taken with digital zoom will only cause more image noise.
Method 4 - Shoot with the Best Possible Camera
The quality of a camera's sensor chip, as well as that of its image compression algorithms, will affect noise levels.
Consider two hypothetical cameras. The first is shooting at 10 megapixels with 3x digital zoom, an outdated sensor, and JPG compression. The second has the same stated megapixelage and digital zoom levels, but uses a higher-quality sensor and outputs images in the uncompressed RAW format. The second camera will produce images with much less unwanted texture. On whatever camera you have, be sure to shoot at the highest quality setting.
Method 5 - A Final Recommendation
It is best to avoid using digital zoom when and where possible. Digital zoom is no excuse to not approach a subject and try to achieve a comparable image using only optics. Provided you have access to software that can blow up photos with pixel interpolation, in-camera digital zoom has no advantage over processing your image on your computer.Popular Cameras for High Quality Photos: