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A digital photo camera have two kinds of zooming capabilities: optical and digital that we presented in other pages . To remind you , an optical zoom uses the arrangement of the lens elements to control the amount of magnification and optical zoom is the specification mentioned first in the camera’s list of features.
The digital zoom is a supplementary magnification system in which the center pixels of an image are enlarged using a mathematical algorithm ( a digital zoom is a software magnification of the captured or focused image ) .
However, digital zoom is a way of turning a 4:1 zoom into an 8:1 (or better) zoom lens even if the results aren’t as good as those you’d obtain with a true optical 8:1 zoom. The digital zoom it’s not so important feature like the optical because many o picture captured with an digital zoom pixilated or bad quality .
If you compare zoom ranges of digital cameras you can be confused because the exact same lens can produce different magnifications on different cameras.
That is the reason why the zoom range of a digital camera is presented either as absolute magnifications or in the equivalents of the 35mm camera lenses that the zoom settings correspond to.
Focal length of a lens ( stated in millimeters) determines the angle of view that the camera can capture and the spatial relationship of objects in the frame. Focal length also affects depth of field or the distance over which focus remains sharp.
The lenses can be categorized by focal length in these groups :
Wide-angle are lenses with short focal lengths , under 35mm. A wide-angle lens has the visual effect of pushing the subject away from you and making it appear smaller. Using a wide-angle lenses you can fit more of the scene into the frame without moving back. Also a wide-angle lens has a large depth of field so that the zone of sharp focus extends a greater distance. For these reasons ( features ) the wide-angle lenses are ideal for landscape photography.
Telephoto are lenses with focal lengths longer than about 70mm that bring the subject closer to you ( increase the subject’s size in the frame and produce a short depth of field) . When is used a Telephoto lens the subject is sharply focused, but distant objects are blurry. The telephoto lenses are great for capturing subjects that don’t permit up-close shooting.
Normal lenses use a focal length in the neighborhood of 35mm ( somewhere between a wide-angle and telephoto ). This focal length produces the angle of view and depth of field that are appropriate for the kinds of snapshots that most people take.
The focal length of a lens tells you the angle of view and magnification , a short focal lengths give you wide angle lenses and a long focal lengths give you telephoto lenses.
You need to know that for 35mm cameras, a normal lens is anything around 50mm, anything shorter than 50mm is a wide angle lens, and anything longer is a telephoto lens.
Another thing that is better to know about focal length is that if you have a 200mm lens and a 400mm lens , both are telephoto lenses, but the 400mm lens magnifies the image much more than the 200mm lense.
So you need to know what focal length (equivalents) do you look for .The focal length you will need depend on what kind of photos you want to take.
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