SLR camera lens how to look at the optical zoom? The maximum number of times?
The third, is the telephoto lens, usually 100mm or 135mm. Which is 100mm lens is generally macro lens, 135mm lens is portrait lens, but focus on the half-length portrait, and 85mm more focused on the body portrait.
SLR camera lens does not look zoom, but look at the focal length. Generally divided into the following:
The first is wide-angle lens. The traditional sense of the wide-angle lens is the focal length of 35mm in the following lens, such as 28mm, 24mm or even 16mm lens. In general, the lens below 24mm are called ultra wide-angle lens. However, because the vast majority of digital SLR on the market is not the full range of digital SLR, the lens of the focal length to multiply by 1.5 or 1.6, so for this type of SLR, 16mm can be considered ultra wide-angle lens.
The fourth, the focal length of more than 200mm is what we call the telephoto lens. In fact, the focal length of the lens is very useful, you can shoot scenery, portrait, or ecological photography (such as shooting birds, etc., especially 300mm or even more than 400mm lens). However, these lenses are usually large and heavy, and the lack of anti-shake help, use the restrictions or a lot, so the actual use of the opportunity is not particularly high.
Lens focal length classification are more common: 8mm, 15mm, 24mm, 28mm, 35mm, 50mm, 85mm, 105mm, 135mm, 200mm, 400mm, 600mm, 1200mm, as well as up to 2500mm long telephoto telephoto lens.
The second is the standard lens. In general, the focal length is 50 mm or 85 mm. 50mm lens perspective with the human eye closest, so called "head". But only because of this, would like to use the header is difficult, because it is not like ultra wide-angle or macro lens that can shoot the human eye can not feel the picture. 85mm lens is generally portrait lens.
