Lens and Focal Length in Photography
Lens and Focal Length determines the distance between the lens and the image sensor. Also, the magnification at which it images distant objects. Usually stated in millimeters like 20mm, 40mm or 100mm. In zoom lenses, the minimum and maximum focal length are of 18mm – 55mm. The shorter the focal length, the greater the area captured and whereas the longer the focal length then smaller the subject appears to be. 
Focal length is the distance from the front of the lens to the sensor. The light is bent in a way that it converges on itself before continuing onto the sensor, when the light falls on it. There is a correlation between the length of the lens and the focal length, but different lens designs can bend the light in different ways. When the subject is far away, the longer the focal length leads to higher magnification and contrarily, the shorter the focal length, then lower magnification is achieved. Whereas, in applications like microscopy, magnification is achieved by bringing the object closer to the lens and a shorter focal length leads to higher magnification. 
The lens is used to bring light to a fixed focal point. There are different types of lens by focal lengths. The Fisheye lens is used for creative and abstract photography with a focal length of 4mm to 14mm. Wide angle lens, used for Landscape Photography and architectural Photography with a focal length of 14mm to 35mm. Standard lens used for portrait, street and travel photography with the focal length of 35mm to 85mm. The Short telephoto lens used for Portrait and street photography with a focal length of 85mm to 135mm. Medium telephoto lens for Wildlife, and Sports Photography with a focal length of 135mm+. The Macro lens is used for close ups with a focal length of 35mm to 200mm. Lastly, the Tilt Shift Lens used for Fine Art and Architecture Photography with an undermined focal length. 
Lens and Focal Length, represents the fundamental descriptions of a Photographic Lens. To learn more about the camera and the technology behind it, one can enroll in Diploma in Fashion Photography.
