Understanding camera lens gives high quality photography. There are lots of distorting qualities of lens which has to be fixed by understanding lenses.
Focal length
We have to understand the focal length. A focal length of a lens is the distance between the center of the optical lens and the image sensor of the camera when focused at infinity. For understanding focal length we also have to understand optical center, it is defined as the point (usually within not always) at which the rays of light entering the lens is assumed to cross. Shorter focal length of a lens provides a wider field of view but it offers less magnification. On the other hand longer focal lengths give a shorter field of view, but it provides a greater magnification. On DSLRs the focal length of interchangeable lens is measured in millimeters. The focal length is displayed on the barrel of the lens, along with the adopter ring’s size.
The lens ratio
If we look upon the front end of the lens barrel, we will see a ratio number (1:2.8-4, 1:2.8, 1:3.5-5.6, etc), these are the maximum aperture of the lens. The amount of light transmitted to the image sensor is determined by the aperture.
The quality of the lens is indicated by the lower maximum aperture value. For high quality lenses the f-stop ranges from f/2 at 35mm and an f/2 at 80mm. For lower quality ranges the f-stop ranges from f/3.5 at 28mm to f/5.6 at 80mm. A lens with better quality has a lower f-number. For example a lens which is “brighter” allows taking photo in low light condition, yet it registers a quality exposure. The bright lenses give us a shallow depth of field. Any lens with f/2.8b or lower is taken into consideration as a professional lens which will have considerably higher price.
Hence the technical understanding camera lens provides a good quality in photography.
