SLR digital camera lens on the 3.5-5.6 what it means
The maximum aperture change value, with the focal length increase the maximum aperture gradually smaller.
Refers to the minimum aperture value of the zoom lens
At the most recent focus, the minimum aperture value is 3.5, and the minimum aperture value is 5.6 at the farthest focus
Refers to the size of the aperture (unit F, such as F1.8 F2.0), the smaller the value the greater the aperture, the greater the aperture the greater the amount of light (according to the photos will be brighter).
Generally this range refers to the wide-angle end of the maximum F3.5, telephoto end maximum F5.6 aperture (the principle is the longer tube light the smaller)
Usually the greater the aperture the lens the higher the price, the better the effect. Such as 50 1.8--50 1.4--50 1.2