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What is a Converging Lens? Photography Basics Explained

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man holding convex lens

If you’re reading this article, you likely want to study the physics of light, the basics of a converging lens, and how it can be of practical use in photography. It can be a bit daunting because of the technical and mathematical principles behind them, but we’ll try our best to simplify it in a digestible manner. Take a look below to learn more and see how it can be a part of our everyday lives. 

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What is a Converging Lens? 

In optics, a converging lens is a lens with either a single convex element or multiple convex elements in its composition. In this scenario, the light collected from a converging lens is refracted in a parallel fashion, which results in an effect that makes the information appear closer or magnified (this is based on the viewing distance). However, the light captured can have a heavy amount of distortion. Converging lenses are also known as double convex lenses.

Examples of a Converging Lens 

One item that showcases the visual effects of a converging lens is the magnifying glass. As you can see on both sides, the lens elements are convex, unlike other types of lenses, which do not have this feature. We also use converging lenses in our eyewear, with many prescription glasses falling in this category. They increase the magnification of your field of view. Other illustrations of a converging lens can be seen through microscopes and camera lenses.

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Image By: markus53, Pixabay

Converging Lens vs Diverging Lens

Contrary to the converging lens, a diverging lens is concave on both its front and back, and the light coming into view will bend outwards. On the other hand, a converging lens is convex on both its front and back, and the light coming through is bent inwards.

How Does a Converging Lens Relate to Photography? 

Converging lenses are used commonly in photography to create a zooming effect that enlarges the appearance of the subject(s) in an image. Most telephoto or standard zoom lenses have multiple glass elements inside of the plastic or metal shell, and there are both concave and convex pieces that shape what the final result looks like. The converging area is the convex piece, and it straightens the light after it passes through the glass. If it weren’t there, the picture would look incredibly distorted and unclear, and the light would bend in ways that aren’t normal to the human eye.

Featured Image Credit: Feng Yu, Shutterstock

About the Author Robert Sparks

Robert’s obsession with all things optical started early in life, when his optician father would bring home prototypes for Robert to play with. Nowadays, Robert is dedicated to helping others find the right optics for their needs. His hobbies include astronomy, astrophysics, and model building. Originally from Newark, NJ, he resides in Santa Fe, New Mexico, where the nighttime skies are filled with glittering stars.