What is the focal length?

Focal length (measured in millimeters) is the distance between your lens’s optical center and your film’s surface. The figure inscribed on the outside of the lens indicates its focal length and it will give you an idea of what the lens is capable of.

Lenses have different properties like glass elements, coating, aperture size, and focal length. Each one has an important role in the grand scheme of things. Specifically, the focal length describes the view angle of the lens or how much it can capture within the frame.

17 mm focal length – ultra-wide angle with the Atoll Art Lens | Photo by Perry Carbonell
35 mm focal length | Photo by Perry Carbonell
60 mm focal length | Photo by Perry Carbonell

Main types of lenses and their focal length ranges:
Standard lenses: 35 mm to 70 mm
Telephoto lenses: 70 mm to 300 mm
Wide-angle lenses: 24 mm to 35 mm

The shorter the focal length of the lens, the wider the view angle is. The higher the focal length, the narrower the view angle. Lenses with a narrower view angle (e.g. telephoto lenses) are great for making objects appear larger. Lenses with a shorter focal length, on the other hand, take in more details within a single frame (e.g. wide-angle lenses).

Other popular types of lenses include:
Macro Lenses: Common focal lengths are 50 mm, 100 mm, and 180 mm.
Ultra-wide angle lenses: Anything shorter than 24 mm.
Fisheye lenses: these are a kind of ultra-wide angle lens that create a distorted image. They typically have a focal length of 8 mm to 10 mm.

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