How Camera Lenses Work? Everything You Need to Know

A camera is useless without a lens. What does lens do? It concentrates light through what you see from the viewfinder into a small, usually 35mm spot at the back of any camera. When there is no lens in the gadget, only white light is generated.

And a premium lens can result in professional pictures even while fitted in a basic camera. On the other hand, an inferior lens can degrade the results from an expensive camera. But do you know how camera lenses work? If not, today’s guide will explain everything.

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What is a Camera Lens? How Do They Work?

This is a tool that directs light on a particular focal point. In mirrorless or DSLR cameras, the lens brings light on a digital sensor, while in film cameras, the lens directs light on the film strip. Lenses are made of an arrangement of glass plates which are either concave or convex.

Characteristics of Camera Lens

The job of a lens is to filter and concentrate light so that it can hit the dedicated areas. But other factors exist that influence how the tool influences the standard and look of pictures. These are as follows:


This term refers to how large the opening is which directs light inside. Aperture is measured in f-stops. These are counterintuitive measurements. The bigger the figure, the smaller the opening will be.

For instance, f/2.8 enables twice the light as opposed to f4. Aperture influences the depth of field. Big openings lead in shallow depth of field, and vice versa.

Focal length

This is a measurement of distance from the sensor to the point of convergence of the lens. The distance is recorded in millimeters. The focal length range expresses how much of the setting your camera can shoot.

Small figures boast a wide angle of the scene and portray more details, whereas high focal lengths are correlated with a narrow angle of view.

Depth of Field

A professional’s helpful tool to grab the viewer’s attention anywhere is regulating the amount of pictures which are in focus. For instance, landscapes are generally captured to add all details. This is why professionals shoot at tiny apertures, such as f16 or f11. Depth of field differs with the category of lens.

Maximum Aperture

This is mentioned on the barrel, and showcases the highest width any lens aperture can open. Generally, lenses with a bigger maximum aperture are expensive. However, such lenses are perfect for dim lighting. This makes it worth every penny.

5 Major Categories of Lenses

Here are the two most common lens types:

1. Zoom Lens

This employs an arrangement of lenses to enable various focal lengths from one lens. This boosts their flexibility, but the speed is mediocre. Zoom lenses include more glass, but they are also bulkier and larger than the below counterpart.

2. Prime Lens

This includes a specific focal length, which boosts sharpness and speed. Even though they are less flexible owing to a set focal length, they are lightweight and quick. It means they are portable.

Within these two categories, other types exist, with their own focal lengths:

1. Telephoto Lens

This is a variant of zoom lens having numerous focal points. It’s great for isolating your subject which is situated at a distance. But this tempting magnification has one drawback – a shallow field of view. Just how telescopes are used to see planetary objects, the telephoto lens focuses on faraway subjects.

Lots of sports photographers employ this lens to ensure a sense of intimacy with the players on the field while they shoot on the sidelines. Some telephoto lenses are bulky, big, and expensive. But many types are available.

2. Macro Lens

This lens is best for creating macro or close-up pictures. Their rare design enables them to generate precise pictures at very close range. Nature photography works best with macro lens as it captures massive details in a single picture.

3. Wide Angle Lens

This is perfect for fitting a big scene in one frame. Wide angle lens is specifically helpful for street or landscape photography. It captures everything unless the subject is in the immediate vicinity of the lens.

4. Specialty Lens

These specialized lenses exude a rare look to pictures. There are different types of specialty lenses. But these are the most common ones:

Infrared lens

This type plays with light instead of perspective. Infrared lenses filter out the light waves excluding infrared to create an extraordinary aesthetic.

Fisheye lens

This is an ultra wide angle lens that can soak in a complete 180° radius surrounding it. The name of this lens is because of how they distort the picture field of view. Even bedrooms appear like a bubble.

Tilt shift lens

This also distorts perspective and makes the details smaller.

5. Standard Lens

This lens is versatile for different photography niches. Their standard focal length ranges from 35mm to 85mm. The bottom of the zoom lens in this range will come with a minimal focal length. This results in a full-frame, wide picture.

Major Lens Specs and Sizes

35mm Lens

35mm Lens

Distortion of space

Lower spatial distortion as opposed to wide lenses. However, it makes objects look far away.

Angle of view


Depth of field

Almost everything is in focus, but not if the subject is positioned near to the camera.


Similar to what a smartphone can capture. 35mm lens is ideal for street photography.

16mm Lens

16mm Lens

Distortion of space

Subjects look farther away, and it makes the objects bigger that are in the immediate vicinity of the camera.

Angle of view

Extremely wide

Depth of field

It focuses and captures everything. No probability of a shallow depth of field.


A wide view of the world. The 16mm lens is ideal for landscape photography.

50mm Lens

50mm Lens

Distortion of space

Minimal or zero.

Angle of view


Depth of field

It’s a breeze to have a deep or shallow depth of field, based on the aperture range.


Similar to how human eyes view. Versatile for all photography niches.

85mm Lens

85mm Lens

Distortion of space

Things appear closer.

Angle of view

Medium telephoto

Depth of field

Getting a narrow depth of field is easy.


Perfect for isolating your subject from the background. The 85mm lens is ideal for portrait photographers.

200mm Lens

200mm Lens

Distortion of space

Things appear very close.

Angle of view


Depth of field

A shallow depth of field unless the subject is at a distance.


Great for choosing a faraway subject, similar to how telescopes do. It compresses the background and the subject.

The Internal Components of Lens

Optical Centre

This is the point where light enters totally flat, without any bending. By tilting the lens or shifting towards the corners of the lens, light is then bent by the lens curves. The light entering converges on the sensor to discover the focus point and create the full picture. Brands selling lenses consider the optical center during construction, adding focus motor effects.

Filter Threads

The lens front showcases a threaded section which enables professionals to fix a lens filter. This component accepts a particular filter size, and is generally noted on the front of the lens barrel. You may choose the lens filter according to your preferences.

Focus Ring

Almost all lenses have this component, which is utilized during manual focus. Some lenses can only offer manual focus, but there is a huge availability of autofocus lenses.

Lens Mount

This critical element is employed to fix the lens on the corresponding camera. Brands have varying designs for lens mount. The auto capable lenses include electric contacts or electronic communication where data is shared from the camera to the lens. Such points enable the camera to regulate the lens and transfer settings back to the gadget that are saved in EXIF metadata.

Aperture Ring

While aperture is employed to adjust the depth of field, its ring enables you to change lens aperture, instead of by camera. Aperture ring was a norm in previous lenses, but the popularity in retro models and videography has made it common again. For instance, Fujifilm has played a big role in the rise of the aperture ring by attaching it to their X-mount lenses.

It’s recommended to utilize the aperture ring on the lens. In videography, the clickless aperture ring allows you to adjust the light entering the lens and depth of field. Lots of videographers hold the lens securely and employ manual focus during recording.

It’s useful to fix the aperture without changing the hold on the lens. Moreover, it’s faster to view the lens to know which aperture is applied to adjust it. Without the aperture ring, you would have to search for the f-stop number on the viewfinder or LCD screen.


Camera lenses are the unsung heroes of photography, translating the world’s beauty and complexity onto a sensor or film. They do so through the manipulation of light, bending and focusing it to form sharp and vivid images. From wide-angle wonders to telephoto marvels, camera lenses come in various forms, each with its unique characteristics.

Understanding how lenses work empowers photographers to make informed choices, experiment creatively, and capture the world in new and exciting ways. So, whether you’re a beginner or seasoned pro, the lens is your gateway to the extraordinary, offering endless possibilities to express your vision through the art of photography.

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