How Does a Camera Work? Your Guide to Photography Basics

Do you want to know how a camera manages to capture photos? This article gives you an insight into how a camera works. Read on!

I do not know about you, but the question “how does a camera work” often pops into my mind. As a photographer, I already have a basic idea about the functions of each camera part. However, I always get curious about how a camera seemingly freezes time and captures a fleeting moment.

That is why I conducted extensive research on this topic. And below, I will share what I learned to help you understand photography better.

Continue reading as I discuss the simple mechanics of how a camera works. 

The Role of Light in Photography

It is essential to understand the role of light if you want to know how a camera works. 

This section will not dive into the complicated physics of light. Instead, I will only talk about the basics.

Light travels in a straight path at a constant speed. However, it can vary in terms of wavelength, frequency, and amplitude, similar to the properties of sound.

In photography, the light passes through the camera. The internal components of a camera collect and capture light in varying amounts. This brightness conveys information in an image.

Our task as photographers is to manipulate how much light enters the film or digital camera. It allows us to achieve different effects and moods in an image.

How Does a Camera Work?

All cameras work roughly the same way, regardless of their type, brand, and cost. 

Both digital and film cameras collect and project light onto an image sensor. After using various ways to process that light, they produce the final image. A film camera offers a photographic film. Meanwhile, advanced cameras, such as smartphone cameras, record images in a digital format.

Cameras comprise several internal components. These allow you to control the amount of light conveyed in a frame. Subsequently, they set the tone of the photograph.

The next section of this article discusses the functions of different camera parts.

Basic Parts of a Camera

Before you start taking photos, it is essential to understand the integral parts of a camera. These include the lens and the light detector surface, which refers to the film or digital sensor. 


The lens is a curved piece of glass or plastic extending from the camera body.

The lens allows light to pass through the camera. It uses multiple internal elements to direct this light onto the sensor. Thus, it plays a major role in crafting how the final image will look like.

However, no lenses are the same. They differ in terms of the amount of glass or plastic used, the quality, and the arrangement of these elements. That is why some lenses can render better images and cost more than others. 

Overall, a lens is one of the most powerful tools of your camera. Understanding how it works is the first step in capturing more beautiful photos.


The aperture is an integral component of a lens. It refers to the opening inside modern lenses that allow light into the camera.

Most modern digital cameras allow you to control the size of the aperture and, consequently, the amount of light passing through the lens. The aperture works the same way as the pupil in our eyes as they dilate or contract to enable more or less light.

The lens aperture is expressed in f-numbers or f-stops, such as f/1.8 and f/6.3. A small f-number corresponds to a large aperture. For instance, a lens with f/2.8 lets more light into the camera than a small aperture of f/16.

Finally, the aperture can affect the depth of field of an image. A large or wide aperture (small f-stop) gives you a shallow depth of field. That means only a tiny area of the frame is in focus, while the rest are blurred. In contrast, a small or narrow aperture (large f-stop) keeps most of the image in focus.

Focal Length

The focal length defines the lens’ magnification power and angle of view. The magnification power describes the size of the individual elements in a photo. Meanwhile, the angle of view refers to how much of the scene the lens can capture.

The focal length is expressed in millimeters. In technical terms, it refers to the distance between the camera lens and the sensor when the subject is in focus.

A long focal length indicates a high magnification and a narrow angle of view. In contrast, a short focal length gives you a low magnification and a wide perspective.

Lenses are commonly categorized in terms of their focal length.

  • Wide-angle lens – It usually has a focal length of 35mm and lower. Wide-angle lenses are ideal for architecture and landscape photography.
  • Standard lens – It offers a focal length between 35mm and 85mm. It is handy for portrait, street, and travel photography.
  • Short telephoto lens– It features an 85mm to 135mm focal length. It can capture portraits and street photos.
  • Medium telephoto lens – It has a focal length of more than 135mm, making them suitable for sports and wildlife photography.
  • Super telephoto lens – It offers a 300mm focal length and higher. Telephoto lenses are ideal for capturing nature and astronomy.

Camera lenses can also have a fixed focal length or a variable one. The former are known as a fixed lenses, while the latter are called zoom lenses.


A camera lens has multiple focal planes that allow the camera to capture a scene. These planes run parallel to the front element of a lens and, in most cases, the sensor. Tilt-shift and wide-angle lenses are the exceptions to this rule, but I will not focus on them in this section.

A lens element moves inside the optic glass to get a particular area in focus. This movement occurs when you manually turn the focus ring in a lens or rely on its built-in autofocus feature. Most lenses have the focusing ring connected to the focusing mechanism to ensure direct control. However, some lenses, usually heavy ones, only offer electronic control.

All camera lenses have a minimum focusing distance from which they can capture a subject. This information is labeled on the front area of the lens in meters (m) and feet (ft). Once your subject is closer than this distance, you cannot achieve proper focus. 


Some high-end lenses feature built-in stabilization. This system uses a floating lens element to minimize the camera motion or shake.

Lens-based stabilization also takes advantage of a gyroscope. It can counteract digital camera movement to give you a more stabilized or steady image.

Another advantage of in-lens image stabilization is smoother performance when using longer focal lengths.

Stabilization systems are different across camera brands. Canon lenses call them IS (Image Stabilizer), Nikon lenses name them VR (Vibration Reduction), Sony lenses have OSS (Optical Steady Shot), and so on.

Size and Weight

Camera lenses also differ in size and weight, depending on several factors. In most cases, a wide aperture means larger lenses.

Zoom lenses are also larger and heavier than fixed lenses. Furthermore, a camera lens with built-in stabilization is bulky and hefty.

Nevertheless, most camera manufacturers design lenses to work in balance with their digital cameras.

Fixed or Interchangeable

Lenses can be fixed to the camera body or interchangeable.

Fixed lenses are common among point-and-shoot and bridge cameras. They can limit the kind of photography you do because you get what comes with the camera.

Meanwhile, interchangeable lenses are available on digital single-lens reflex (DSLR) and mirrorless cameras. These come in different types to suit most photography genres.

Interchangeable lenses also have a unique lens mount. This component allows you to connect the lens to the camera body. It can vary depending on the camera manufacturer or brand. For instance, Canon offers EF/EF-S lens mounts for their DSLRs and RF for mirrorless systems. On the other hand, Nikon uses an F (DSLR) and Z (mirrorless) lens mounts.

Camera Body

Once the it passes through the lens, the light travels toward the camera body. Some of the light waves hit an internal mirror to reflect the image into a viewfinder (to be discussed later). The rest of the light hit the sensor, where they undergo image processing.

The camera body comprises all the internal parts of your digital camera. It does not include the lens and other detachable components.

Below, I will discuss the functions of each digital camera part.


All digital single-lens reflex (DSLR) cameras and most mirrorless systems have viewfinders. These can be either optical or electronic.

A DSLR features an optical viewfinder. It uses several internal mirrors that reflect the light to show the scene in front of you. It offers an accurate image without delay. Thus, it gives you better clarity and dynamic range.

The only downside of an optical viewfinder is that it blocks the view when you snap a picture. That is because the mirror flips out of the way once you press the shutter button. 

Mirrorless cameras do not have mirrors inside their bodies, hence their name. They rely on an electronic viewfinder (EVF) to let you see the live preview of a scene. This type of viewfinder converts light waves into digital images, leading to a slight delay. EVFs also do not perform well in low-light conditions. 

On the positive side, electronic viewfinders show what the exact image looks like when photographed. They are unlike OVFs, which display the scene in front of the lens. EVFs also offer a preview of the depth of field and focus distance, similar to an LCD screen.


The shutter is a gate-like mechanism that opens and closes to reveal the image sensor underneath. It can swing out of the way to allow light to reach the image sensor. The duration for which it exposes the sensor beneath will depend on your shutter speed.

A fast shutter speed, like 1/1000th of a second, gives you a short exposure time. It only allows a small amount of light to hit the sensor.

On the other hand, a short shutter speed, such as 1/50th of a second, offers a long exposure time. That means more light can enter the camera sensor.


The digital camera sensor is an integral part of modern cameras. It refers to the small rectangle hardware inside the camera body, directly behind the lens. 

The sensor captures light and converts it into an optical image you can save on a computer or memory card. 

The sensor size dictates how much light is used to create the photograph. A large sensor can collect more light and information than a small sensor. Thus, full-frame cameras (with larger sensors) produce better image quality than the crop or micro 4/3 digital sensors.


ISO pertains to your camera’s sensitivity to light. 

All cameras offer different ISO values or ISO speeds to use. Below is a common ISO range among most modern cameras.

  • ISO 100
  • ISO 200
  • ISO 400
  • ISO 800
  • ISO 1600
  • ISO 3200
  • ISO 6400

A lower ISO has less light sensitive materials. Meanwhile, a higher ISO value means the sensor is more light-sensitive. 

When you double your ISO speed, you receive twice the image’s brightness. For instance, a photo taken at ISO 400 will be twice as bright as ISO 200, which will be twice brighter than ISO 100, and so on.

However, using a high ISO value (or faster ISO speed) in most digital cameras is not always ideal. It introduces a lot of grain, also known as noise, into your picture. So before raising your ISO, consider adjusting the aperture and shutter speed first to achieve a properly exposed image.

Image Processing

After the light hits the digital sensor, it starts converting the light waves to electronic data. This process is known as the analog-to-digital format converter.

Most cameras can offer data with a 16-bit dynamic range but only use 14 bits. The extra two bits give you more flexibility in the editing and filtering stage.

A 14-bit data means that there are 16.384‬ possible values for every pixel. It ultimately provides a wide color and tonal range.

This pixel data undergoes image processing. Then, it gets written onto your card for convenient preview and sharing in your preferred digital technology device.


Cameras come in different types. They have also evolved a lot throughout the years, which drastically changed photography. However, the basic principles remain the same.

Understanding how a camera works can help you utilize its capabilities. It can also open up more possibilities when taking photographs.

I hope this article answered your question “how does a camera work?” in clear detail! Feel free to share it with other photographers if you find the post helpful.