Understanding Focal Length Range

The focal length of a lens is measured in millimeters (e.g., 35mm) and indicates its magnification power and angle of view. A super telephoto lens has a long focal length (e.g., 300mm) while a wide-angle lens has a short focal length (e.g., 20mm). Zoom lenses let you change the focal length, so they have a focal length range (e.g., 18–55mm).

All-in-One-Zoom - Sometimes referred to as high-power zoom lenses, these versatile zoom lenses cover a very broad focal length range (e.g., 18–200mm DX or 28-300mm FX) for maximum versatility. They are a great choice for someone who wants a single lens that can shoot the widest range of subjects.
Wide Angle - These zoom and prime lenses have wide angle capabilities (e.g., focal length’s <35mm ). They are great for capturing wide scenes like landscapes, skies, interiors, architecture and group shots.
Standard - These zoom and prime lenses cover the “standard” part of the focal length range (~35–50mm). They produce an angle of view similar to our eyes and are highly versatile all-around lenses.
Telephoto - These zoom and prime lenses will get you closer to your subject; the higher the focal length value, the greater the magnification effect. For reference, a 200mm lens will let you capture great close-up shots of sports action from the sidelines.
Super Telephoto - These ultra-high-powered zoom and prime lenses give you maximum magnification power and are prized by nature and sports photographers.