Before you begin shooting and putting your camera to use, it’s always good to know what exactly makes your camera tick. If you’re a beginner to photography, it is important for you to have a technical understanding of your gear as it will help you set up the essential foundations you need to begin shooting. This article will teach you all the necessary basics from the focal length of your lenses to shutter speed and aperture. We invite you to explore other articles as well to learn more about DSLR and mirrorless cameras.

Video: How Does a Camera Work? | Photography 101

The video above is an excerpt from our Photography 101 workshop, an A-Z guide to photography. In this course, we explore the fundamentals of portrait photography and take you on 6 real-life photo shoots, going behind-the-scenes to show how we composed the frame, posed our subjects, and exposed each image.

Roadmap for Understanding How Cameras Work

  1. DSLR Vs. Mirrorless Cameras
  2. Sensors
  3. Exposure
  4. Lenses & Focal Length
  5. RAW Files Vs. Jpegs

1. DSLR Vs. Mirrorless Cameras

Let’s first take a quick look at the two most popular types of cameras in use today (not including smartphones) that give us the most control over how we create imagery: DSLR cameras and Mirrorless cameras. If we’re to understand how a camera works, we should know the difference between these two camera bodies.

Note, we will not go into detail to distinguish the autofocus systems of these cameras here, but you can learn more about these features via links to other articles included in each section below.

How Does a DSLR Camera Work?

So, what is a DSLR camera? DSLR stands for digital single-lens reflex – or a digital SLR camera. It is a digital camera that combines a digital imaging sensor with the mechanisms and optics of a single-lens reflex camera.

DSLR cameras use a fixed digital sensor, hence the inclusion of “digital” in the name. These cameras also only use one lens for focusing, framing, and capturing the photo. In case you’re wonder what reflex means, it refers to the use of a mirror to direct the light coming in towards the viewfinder, which then gives an optical view of what you’re capturing. The reflex element sets DSLR cameras apart from mirrorless (and other digital) cameras.

Here’s a great video from Fstoppers that details exactly how DLSR cameras work.

How Does a Mirrorless Camera Work?

Mirrorless cameras typically refer to digital cameras with interchangeable lenses and use an electronic viewfinder rather than a traditional viewfinder. The name mirrorless stems from the fact that they do not have a reflex mirror or optical viewfinder like a DSLR camera.

In a mirrorless camera, light passes through the lens and goes directly into the digital sensor. It then displays directly on the camera’s LCD screen, giving us a live preview of the image through the electronic viewfinder. Because mirrorless cameras do not include a mirror box inside the camera, they tend to be smaller than DSLR cameras.

Learn more about mirrorless cameras and the benefits of using them in this overview of mirrorless cameras on our site.

[Related Reading: Best DSLR & Lenses For Beginners | 2021 Update]

2. Sensors

Your digital camera’s sensor represents one of its most important elements. Camera sensors vary in size, and the image quality and other factors are directly tied to your camera’s sensor.

So, what do camera sensors do? Camera sensors capture and convert light into electronic signals that render an image. Sensors contain millions of light-sensitive photosites that capture the light that passes through the lens. The sensor size determine the amount of light used to create an image. A larger camera sensor can hold more information, which typically allows for better quality images.

When exploring sensors, you’ll need to familiarize yourself with full frame and crop sensors. Crop sensors, which are smaller than full frame sensors, crop the scene (see the example image above) while larger sensors capture a larger frame. A camera’s sensor size plays a role in determining several important factors, including resolution, image size, field of view, depth of field, the size of the camera, and more. Find our in-depth look at full frame vs. crop sensors here.

3. How Does a Camera Work: Exposure

If you just picked up photography, you may not have yet heard of the “exposure triangle.” The three components included in the triangle (Aperture, Shutter Speed, and ISO) comprise the key to understanding how to use cameras. We’ll explore each element in more detail below.


The aperture of a camera is the opening of a lens’ diaphragm through which light passes. It opens and closes accordingly to control the amount of light that is coming into the camera.


Opening and closing your aperture also affects your images from an artistic standpoint. If you’re shooting with a wide open aperture, your foreground will be more in focus than your background; whereas if you were to shoot with a closed aperture, everything in the scene (foreground and background) would be sharp.


The blurry quality that end up getting in your images when shooting wide open is called bokeh (BOW-keh).

Shutter & Shutter Speeds

The shutter on your camera is what controls the duration in which the sensor inside your camera will be exposed to light. Using different shutter speeds when taking your images will not only control how long your sensor is exposed but it will also render different visual effects. The longer or slower your shutter speed is, the more motion you are able to capture. The shorter or faster your shutter speed, the more action you are able to freeze or stop.




Last but not least on the list of exposure triangle components, we find ISO (International Standards Organization). ISO deals with the sensitivity to light for film or digital sensors. Basically, a lower ISO number implies the film or digital sensor is less sensitive to light while a higher ISO number means the opposite. When adjusting ISO, one stop of light is equal to either double, or half, the current ISO number. In other words, IS0 100 is one stop darker than ISO 200. Similarly, ISO 400 is one stop brighter than ISO 200.

In addition to its impact on the sensitivity to light for film and digital sensors, ISO also plays a significant role in the areas of image quality and noise. We discuss these factors and share recommendations for how to balance ISO with shutter speed and aperture in this in-depth look at ISO on our site.

[Related Reading: What Is Exposure: The Ultimate Guide To Creative Use Of Exposure]

4. How Does a Camera Work? Lenses & Focal Length

When talking about lenses, one of the first things that come to mind is the focal length. The focal length simply defines the effective view of the lens, and it is always measured in millimeters (mm). So, when you’re looking at the numbers on any lens, the lower the mm number, the wider the angle or field of view, and the higher the mm number, the tighter the angle.



5. RAW Vs. Jpeg Images

Once the image hits the sensor, it is run through what is called the buffer inside the camera which then processes the image into a JPEG before it is stored in the memory card. Shooting JPEG means the image will be raw processed and converted while in the buffer, while shooting RAW means the image will skip processing and transfer directly from the buffer to the memory card.


Learning how your camera works is just the tip of the photography iceberg, and we’ve just skimmed the surface here. If you’re looking to dive deeper into your photography education, check out our Premium subscriptions, which include streaming access to over 30 courses, training systems, and more on topics that range from fundamentals like composition, posing, and lighting to building a business.