Photography 101: Focal Lengths

The left photo was taken with a 16mm fisheye lens while the right photo was taken with a 24mm lens. © F. M. Kearney
The left photo was taken with a 16mm fisheye lens while the right photo was taken with a 24mm lens. © F. M. Kearney

By F.M. Kearney

In last month’s Photography 101 article, I discussed what I consider to be one of the most fundamental basics of photography: apertures and shutter speeds. Following closely behind in terms of importance are focal lengths. Simply put, the focal length describes the angle of view of a lens, as compared to natural eyesight. It’s a measurement (expressed in millimeters) of how much of a scene it captures. A long focal length lens, such as a 200mm lens, captures a narrow angle of view, or an enlarged view of the subject. These types of lenses are known as telephoto lenses. A short focal length lens, such as a 28mm lens, captures a much wider angle of view, making the subject appear smaller. As their angle of view implies, these types of lenses are known as wide angle lenses. Lenses that encompass multiple focal lengths are known as zoom lenses. They are easily identifiable with ranges such as 12-24mm, 24-70mm or 100-300mm. A variety of focal lengths can be achieved simply turning or sliding a ring on the lens.

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