Most of the digital cameras within the mid-priced range include a 3x/4x lens - the first number refers to the optical zoom with the second number referring to the digital zoom. A few of the lower-end priced cameras have only a digital zoom, but their photos are rather dull and slightly fuzzy. The zoom effect in a digital camera is similar to, yet different, from that of a conventional camera. It brings distant subjects closer.
However, in a digital camera there are two kinds of 'zooms'. The first is similar to that of a conventional camera and is known as the optical zoom. The second is the digital zoom, and is more interesting. It 'simulates' optical zoom by enlarging a portion of the image -- that is the digital zoom selects a portion of the photograph and blows it up.
The zoom effect should not be confused with photo editing, where an image editing software is used to crop and blow a picture on a computer screen. Cropping a picture can refer to enlarging the main subject, or an area of choice - thereby eliminating the remaining parts. Another misconception associated with digital zoom is that it is very handy in capturing long distance images. Nothing can be more misleading. Optical zoom matters more in a digital camera.
The zoom that should be used for comparing cameras is optical zoom, and not digital zoom or total zoom. A camera's quality depends upon the value of optical zoom; a camera with higher optical zoom is better than a camera with lower optical zoom. In fact, today the digital camera manufacturers have started using a new term - "total zoom." This term only confuses the customer for there is nothing like total zoom. At best, it can be used to indicate the fact that a digital camera has both kinds of zoom - optical zoom and digital zoom.
Individuals who previously used the 35mm camera or an APS camera used only optical zoom. This uses the lens to bring the subject of the picture closer. Digital zoom are associated with the digital video cameras.
Many photographers do not really associate digital zoom as "zoom" in the digital cameras, as it only enlarges a portion of the image. In layman's terms, the camera crops a certain aspect of the image, and then enlarges it back to size which causes a loss in image quality. But what it actually does is replace the image editing for cropping.
Another zoom effect that has been developed recently is the "smart zoom". This particular zoom maintains the image quality by avoiding interpolation of the image. However, smart zoom works only if you select an image smaller than the full available image size.
Sometimes optical zoom is compared to resolution while buying a digital camera. Nothing can be more absurd. These are two different values and have no common link. Resolution is used to indicate the number of pixels in an image while optical zoom is used to define the lens power. It can neither increase nor decrease the resolution.
There is also a tendency today to disable digital zoom. Some photographers prefer to crop and enlarge an image on a computer screen. They don't trust the camera to do it for them. This is not a good practice because it reduces the effectiveness of your camera.
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