How Digital Cameras Work

Imagine social media, webshops or news websites without images. Digital photography has a huge impact on our lives today. Taking a good photo can be the first step to finding your new job (LinkedIn), making a business successful (eBay, Amazon), or getting laid tonight (Tinder).

From a hairdresser’s point of view I found out that doing photo shoots helps a lot when picking the right hairstyle and gives valuable feedback for post-haircut styling & maintenance. Getting to know my camera has dramatically improved this process.

In this article I will try to briefly explain how digital cameras work and share a few tips that will help you take better photos.

Putting the Real World into an Image File

An image file is basically a collection of dots with different colors. Each dot is a pixel on your screen. For example, a photo with resolution 2048×1536 has 2048 pixel columns (width) and 1536 pixel rows (height). This is in total 3,145,728 pixels, or 3.1 Megapixels.

Digital cameras convert light into a collection of pixels. When the shutter button is pressed, the shutter opens and light gets projected on the sensor inside. In a 3 Megapixel camera, for example, this sensor is divided into a fine grid of 3 million cells. Each cell collects a tiny portion of light and generates a single pixel of certain color. All pixels, together, compose the digital image as an end result.

Camera Exposure

Exposure determines how dark or bright an image will appear. It can be controlled by adjusting the shutter speed, aperture, or ISO.

1. Shutter Speed (Exposure Time)

This is the duration for which the shutter stays open. The longer the time, the more light hits the light sensor, which results in a brighter image. Here you can see a picture taken with three different exposure times:

Increasing the exposure time is essential when taking night photos because the amount of light is very low.

2. Aperture

The aperture determines how wide the entrance pupil of the lens gets open. A wider opening will result in a more concentrated focus, i.e. the background will be blurred. This effect is called “shallow depth of field”.

Wide aperture: If you look closer at the table profile, you will see how thin the focused region is. All the details in front of it and behind it get heavily blurred.

Narrow aperture: Preserves much more detail further away from the focused object. The table profile is sharp and the background objects are easy to distinguish.

Controlling the aperture can be useful when taking portrait photos. Sometimes the background is too detailed and steals the attention of the viewer. In such cases, increasing the aperture brings more emphasis on the subject of the photo. Try keeping the focus on the eyes of the person, this will give your photo more character.

On the other hand, narrow aperture is preferred when taking landscape photos to keep the objects in the far distance sharp.

Be aware that on most cameras aperture is measured in F-stop values. Contrary to expectations, lower F-stop values stand for wider apertures.

3. ISO

The ISO setting controls the camera sensitivity to light. Increasing the ISO value produces brighter photos, but very high ISO can reduce the quality of the photo.

Tweaking the Settings

It is important to note that changing one of the above mentioned settings often requires adjusting some of the others. For example, increasing the aperture may require reducing the exposure time to optimize the amount of light that goes through the lens.

Camera Modes

All cameras nowadays have an automatic mode (A) which tries to choose the optimal settings for a given situation. If this option does not produce the desired result, it is a good idea to try one of the predefined modes (e.g. portrait, landscape, macro).

Some devices allow full manual operation (M) but this is not recommended to use, unless you really know how the different settings affect each other.

In many situations a good approach is to change just a single setting (only aperture or only shutter speed) and let the camera optimize the rest of the settings. To do this, you can use the Aperture Priority (Av) or Shutter Priority (Tv or S) modes. For example, if you want to take a portrait photo with blurred background, you can switch to Av mode and select a wider aperture. The camera will take care of the other settings accordingly.

Final Words

This article focused on the basics of digital photography. Knowing how cameras work helped me with my hairdressing photo shoots and will help you with your next LinkedIn profile pic. Stay tuned for more articles on how to hold your camera (-;