Digital zoom technique

1, to say what telephoto and wide angle are, we must first understand the focal length. In fact, when people talk about the focal length of a digital camera, they are not talking about the actual focal length of the digital camera, but about the equivalent focal length, that is, the focal length relative to the traditional 135 camera. From the principle of photography, the smaller the focal length, the wider the field of vision, and the wider the range of scenery that the photo can accommodate; The larger the focal length, the narrower the field of view, which means that you can shoot distant objects.

2. Generally speaking, in a lens, if the focal length is in the range of 80mm to 300mm, it can be called telephoto lens, and if it exceeds 300mm, it can be called super telephoto lens. In today's digital age, various definitions are different from the traditional ones, so a digital camera with a focal length of more than 200mm, which is equivalent to the international traditional 35mm camera, can be called a telephoto machine. Now there are many digital cameras with a focal length of 350mm or even 432mm, which brings great convenience to people when shooting at a long distance. With the help of telephoto or even ultra-long focal length lens, not only distant objects can be photographed, but also telephoto with appropriate aperture parameters is convenient for taking excellent portrait photos.

3, and the so-called wide-angle lens is a lens with short focal length and large viewing angle. Generally speaking, a lens with a focal length less than 35mm corresponding to a 135 camera can be regarded as a wide-angle camera, but in a digital camera, it usually goes directly to 28mm below 35mm, so in many cases, a digital camera with a focal length less than 28mm is customarily called a wide-angle digital camera. Wide-angle lens can produce the effect of big prospect and small prospect. The distortion of the picture produced by wide-angle lens exaggerates the foreground object, highlights the foreground object more, and gives people a strong visual impact. Therefore, the wide-angle lens is mainly suitable for taking photos of larger scenes, such as architecture, scenery and other themes.

Thirdly, the clarity of photos depends on three aspects: first, the optical performance of the lens; The second is the area size and color depth of the photosensitive device; The third is the technical level of the image processor. It can be seen that whether the photo is clear or not does not depend on the length of the lens size or the size of the optical zoom. In fact, the larger the optical zoom, the longer the lens and the lower the image quality.