How Do Cameras Work? A Guide for Beginners

How Do Cameras Work? A Guide for Beginners

how do cameras work? a guide for beginners

Want to know how cameras work yet don’t want to read about complex mathematics and physics? This is actually the guide for you.

In this article, I’ll describe how most cameras work, and I’ll also clarify the differences between various digital camera types (such as film versus electronic and DSLR versus mirrorless ). With this knowledge, you can make an informed choice before buying a new camera – in addition, you can better understand what’s going on inside your equipment!

If you’re ready to get going, let’s dive in.

How do cameras work?   The basics

If you look at the giant digital cameras used by photography pioneers, then you check out the latest iPhone camera, you might think they don’t have something in common.

But in reality, the basic concept of how cameras work hasn’t changed much. Put simply, the light reflected from the subject goes into the camera through a pit; it’s then projected in the back of the camera, where it’s registered by a light-sensitive material (whether a digital messfühler or film).

This core process offers stayed the same since the creation of photography, though the details have changed. Let’s from the very beginning, then build as much as modern-day camera equipment.

The camera obscura

Camera obscura
Source: Wikimedia Commons

The particular forefather of the photographic camera was the camera obscura, first created in 1545 based on a principle that goes back to around 400 BCE.

The first camera obscura was just a dark room with a hole with the walls. Whatever was outside of the room would be projected through the hole onto the opposite walls. Because light travels in a straight line, the projection would be upside down, as you can see within the diagram above.

Over time, the camera obscura became smaller – rather than whole rooms, it was manufactured from boxes – and was used to aid artists whenever drawing.

The particular pinhole camera

Pinhole camera - How do cameras work
Source: Wikimedia Commons

A digital camera obscura is just a box using a hole that allows light in order to project on the opposite side – but once you include a light-sensitive material, you do have a pinhole digital camera .

It’s a simple item you are able to create with a shoebox (or any box) painted black. Use a needle or a pin number to punch a small pit, then place a negative movie or a sheet of photographic paper at the back to sign-up the image projected inside.

In essence, this is how any photographic camera works, even the latest models. Of course , some elements have evolved, when i explain in the next section:

Photographic cameras

simple DSLR diagram
The basic DSLR components.

All cameras, old and new, work under the same principle: light comes through a hole and projects an image on the back of the camera. But different models feature different details, and I can’t go into all the developments, therefore please bear with me as I talk generically.


Unlike pinhole cameras, most current digital cameras have a lens. Lenses generally include multiple glass components that bend the light to get a sharp, focused image.

The quality of the cup, the way it’s arranged, as well as the amount of glass inside the lens can impact the quality of the final image. This is one of the reasons why several lenses are more expensive than others.

By moving the zoom lens glass, you can focus the image. And in some (zoom) lens, you can also change the focal duration.


Modern lenses contain an aperture , a hole that allows in light. In many cameras, you can control the size of the aperture, much the same method as the pupil in our eyes dilates or contracts in order to let in more or much less light.

The lenses that allow for wider maximum apertures are more expensive and are commonly known as fast lenses. Note that the aperture is expressed in f-numbers, like so: f/1. 8, f/2. 8, f/6. several, f/9, f/16, etc ., where smaller f-numbers correspond to bigger apertures.


As gentle moves through the lens towards the camera body, it won’t simply impact the particular camera sensor or movie. There’s a barrier that opens and closes in order to block the light or enable it through, called the shutter .

Most shutters contain two curtains. When you press your camera’s shutter switch to take a photo, the first curtain slides up to expose the particular sensor or film to light. Once a predetermined amount of time has passed (the shutter rate ), the 2nd curtain covers the sensor or film, and the image-making process stops.

Film/Sensor and ISO

When light gets to the back of the camera, this gets recorded by the movie (analog cameras) or the sensor (digital cameras).

I won’t get into much detail here, mainly because I’ve discussed this detailed down below. I will tell you, however , that films and sensors can have different sensitivities in order to light, called ISO (or ASA).

By the way, ISO is the third factor you need to consider when exposing a photograph. The INTERNATIONALE ORGANISATION FÜR STANDARDISIERUNG, along with the aperture and the shutter speed, form the exposure triangle .

Film vs digital cameras: what’s the difference?

many types of cameras

These days, digital cameras is much more popular than film digital cameras – yet some photographers still prefer film, and the technology is more similar compared to you might think.

The main difference between film and digital camera models is the medium that registers the image. Digital cameras have a messfühler that stores the image as data, while analog digital cameras use photosensitive film.

A digital camera utilizes one sensor – when the camera is built, there’s simply no changing it. But analog cameras offer all sorts of movie types. You can load a traditional camera with negative film (black and white or color), slide film (also known as color reversal and black and white reversal), or infrared film.

Naturally , before you load an analog camera, you’ll need to decide which type of film you want to make use of, how sensitive it should be (the ISO/ASA), and how many images you want (conventional film comes offer 12, 24, or even 36 exposures).

You can make some changes after, such as pushing or pulling the film, as well as mix processing. However , these adjustments affect the entire roll but not a single photo.

With digital cameras, you can modify nearly every setting from picture to image: the INTERNATIONALE ORGANISATION FÜR STANDARDISIERUNG, image quality, file format, and whether the shot is in colour or black and white.

Photographic film comes in different sizes (35mm, 120mm, 4×5, etc . ). In the same way, you can get different digital sensor sizes ; Ill talk more about them in an afterwards section.

Let me emphasize that film is just not better than digital or vice-versa. It’s a matter of personal preference, style, and storytelling.

Types of digital cameras

Photographers use many different camera types, but for the particular purposes of brevity, I’ll skip the large- and medium-format cameras and focus only on the most common options.


Canon DSLR camera with lens

DSLR means digital single-lens reflex, that is the digital counterpart from the popular SLR film digital camera. DSLRs use interchangeable lens, and the lenses from a DSLR often work on an SLR CAMERA and vice-versa.

The most distinctive characteristic of the DSLR is a reflex system that allows you to see exactly what you capture through the viewfinder. On the outside of the camera, you will notice a bump, under which sits a series of mirrors. On the inside, the light that comes through the lens hits a mirror in the back of the camera. This mirror is positioned at such an angle that it reflects the sunshine up toward a pentaprism, where it bounces to achieve the viewfinder.

When you push the shutter button on a DSLR, the mirror flips up to let the light pass through to the sensor. That’s why, throughout a DSLR exposure, you can’t discover anything through the viewfinder.

Mirrorless cameras

Olympus mirrorless camera

Since the name suggests, mirrorless cameras don’t have a mirror in front of the sensor.

Mirrorless cameras are relatively brand new, and prior to the last few years, they were considered amateurish because the quality didn’t match that of a DSLR.

Nowadays, mirrorless cameras have full-frame sensors much like DSLRs, so the main distinction is the size – mirrorless cameras tend to be far smaller than DSLRs – as well as the viewfinder. You see, because mirrorless cameras don’t feature the mirror used by DSLR technology, there’s no “true” viewfinder image; instead, higher-end mirrorless cameras offer a feed to the camera sensor (so you are able to preview the image), although some entry-level cameras don’t have a viewfinder at all. (In these case, you can preview the image on the rear LCD display screen. )

Optical viewfinders (DSLRs) and electronic viewfinders (mirrorless) offer different advantages and disadvantages. I won’t get into the details here, but be enough it to say that both work great for pro-level work, and you can rely on either approach to beautiful results.

Bridge cameras

Bridge cameras in many cases are called “superzoom cameras, ” because they generally feature a wide range of focal lengths – although unlike DSLRs, you can’t exchange out the lens.

And while bridge cameras are built like DSLRs, they often don’t have an optical viewfinder.

The sensor is often small, and to this very day, there aren’t any full-frame bridge cameras. In fact , bridge cameras are halfway in between a DSLR and a compact camera – hence title, “bridge. ”

Point-and-shoot cameras

Fujifilm point and shoot camera

Point-and-shoot cameras, also called compact digital cameras , may offer a few manual control – but they’re meant to be used in Car mode, and they’re all about ease of use. You simply point the particular camera, press the shutter button, and get a photo.

Point-and-shoot cameras have a fixed lens, and while they’re quite small in size, they have become somewhat irrelevant since smartphone cameras have sophisticated in power and recognition.

Digital camera sensors: why do these people matter?

Photographic camera sensor

In the back of every digital camera is really a sensor that records light, and you see the result being a digital photo.

A camera sensor is a grid of photosites that will capture photons and transform them into a voltage value. This information is later processed in different ways according to the type of sensor – currently, they could be CCD or CMOS, even though CCD is becoming less typical.

Each photosite is called a pixel ( sensel is a more technical term, but this article is meant to be an introduction, so I’ll stay with the commonly used pixel ).

When you see that a camera has 24 megapixels, it produces images formed by 24 million -pixels. Don’t be tempted by a higher pixel count, though. You’ll have bigger images, yes – but they won’t necessarily be better. Let me elaborate.

Megapixels and image quality

In the event that all camera sensors function the same way, then what’s the difference? Why should you buy one digital camera sensor over another? The key reason is that sensors come in various sizes, and so different detectors have different-sized pixels.

Have you ever pondered why some smartphones have 108 MP and professional cameras only have 30 or even 40 MP? It’s since the pixels in that 108 MP smartphone are tiny , whereas the particular pixels in a 30 MEGA-PIXEL full-frame DSLR are much bigger. Most people know about megapixels plus think that more MP equates to better image quality, so smartphone camera manufacturers maintain increasing the pixel count, but this isn’t always the best thing.

How do the particular sensor size and -pixel size impact your digital photography?

  • Bigger pixels (usually found in bigger sensors) have a better high-ISO performance (though note that newer cameras generally offer much better high-ISO performance over old cameras, so a small, brand new sensor may be superior to a huge, old sensor).
  • At high ISO beliefs, small pixels lose substantial dynamic range .
  • Larger sensors feature a shallower depth of field than smaller sensors, assuming the image is identically framed. This can be an advantage or a disadvantage based on your needs.
  • Smaller sensors mean that you have to apply a crop aspect to your lens, effectively giving it a longer focal length. For example , a standard 50mm lens on a full-frame camera becomes a 75mm telephoto on a standard APS-C camera. Again, this can be advantages or disadvantages depending on what you want to capture.

Sensor sizes

Sensor size comparison how cameras work
Source: Wikimedia Commons

Sensor sizes are not standard, and you’ll discover that each manufacturer makes their very own rules. However , here are some classes that you can use as a starting point:

Medium structure : Only certain specialists use sensors this huge, so I won’t go into a lot of detail. However , it’s crucial that you know they exist. The particular sensor sizes range from 43. 8 x 32. 9 mm to 53. 7 x 40. 2 mm.

Complete frame : These sensors are the equivalent of 35mm film, which is 36 by 24 mm. It’s the normal size found in professional DSLRs and mirrorless cameras.

APS-C : These are commonly known as cropped sensors , because they’re clipped in comparison to full-frame sensors. The size varies according to each brand, but many manufacturers, including Nikon, Sony, and Pentax, make use of 23. 6 x fifteen. 6 mm, while Cannon uses 22. 3 x 14. 9 mm.

Four Thirds/Micro Four Thirds : This standard was created by Panasonic and Olympus so that lenses could be compatible across manufacturers. The size is 17. a few x 13 mm.

Sensors used in link cameras, point-and-shoot cameras, plus smartphones are less consistent in size, but they are generally smaller than the Four Thirds regular.

How digital cameras work: final words

As you can see, cameras can be complicated! But hopefully, you now have a better understanding of how cameras work, and you learn how to pick a camera of your own.

Now over to you:

Do you have a favorite camera type? Would you shoot with digital or even film cameras? Share your ideas in the comments below!

Learning much more from our Ideas & Tutorials category

Ana Mireles

Ana Mireles

is a photographer and creative researcher. She has been granted and exhibited in South america, Italy, and the Netherlands. Through theory and practice, the lady explores the cultural facet of photography, how it helps all of us relate to each other, the world, plus ourselves. She has also an enthusiasm for teaching, communication, and social media. You can find more about the girl and her work at her web site or acquire some of the girl works here .

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