The zoom capability on today's modern cameras is probably one of the easiest features to learn and the most fun for the new photographer. With the latest digital cameras, photos of a distant object can appear as if they are much closer.
Zoom Ability
The built-in zoom feature of a self-contained digital camera will be measured by its magnification power, labeled as 3x, 6x or even 12x. The labeling shows the zoom ratio provided by the camera. Note, too, that similar measurement zooms may differ in performance between cameras. Depending on the construction, different materials and camera designs will produce marginally different pictures between brands. Also one brand may have a wider angle lens then another with the same zoom capability. The result, again, is different photos.
Also, some cameras use optical zoom, which is the traditional magnification caused by moving glass lenses inside the camera. Others offer digital zoom, which uses a computer algorithm to guess what a zoom image should look like. The optical image is better on a quality basis.
Zoom Focal Length
Every camera, from digital to single-lens reflex (SLR), has a focal length. This is the distance from the camera lens' optical center to the focal point. In digital cameras, the focal point will be the sensor that picks up the image being photographed. The longer the focal length, the bigger the magnifier, such as 6x or 12x.
Fixed vs. Adjustable
Most cameras with a static, built-in lens (nondetachable) have a fixed focal length. Those with a lens that adjusts or can be changed a longer zoom lens would be adjustable.
Capability
A switch on the camera's body triggers the zoom capability on digital cameras, pushing the lens out from the camera (increasing magnification) or drawing it back (reducing magnification). In SLR, or manual, cameras, adjusting the zoom is done by hand.
Some Problems with Zooming
Higher zoom abilities can compromise photo quality. The first issue will be the shake factor. The longer the lens, the more vibration that can takes place, making it harder to take a clear picture. Good cameras compensate with anti-vibration features. Second, maxed-out zoom shots degrade the edge of a photo and suffer from less light entering the lens. A faster shutter speed or artificial light offsets this effect.
Tags: digital cameras, focal length, zoom capability, focal point, from camera