Pixels are the basic building blocks of digital photos. Every digital photo is made up of a grid of tiny colored dots called pixels. The word "pixel" comes from the words "picture" and "element", which means that a pixel is the basic unit of a digital image. In barrel cameras, the resolution is measured in millions of pixels, i.e. megapixels. The average of current cameras is somewhere between 15 and 30 mega-pixels.


The meaning and function of pixels in digital photography

Image resolution
The resolution of a digital image is measured in pixels and determines how many pixels make up the image. The higher the resolution, the more detail can be captured and displayed. For example, an image with a resolution of 1920×1080 (Full HD) is 1920 pixels wide and 1080 pixels high, for a total of 2,073,600 pixels. So a good two mega-pixels.

Color depth
Each pixel in a digital photo contains color information. Color depth determines how much color information is stored for each pixel. Higher color depth allows for more accurate color representation. The most commonly used color depth in modern digital photography is 24-bit color depth, which allows up to 16.7 million colors to be displayed. It is also important to note that increasing the color depth (to say 48 bits) drastically increases the file size.

Capturing the light
Digital cameras use sensors to capture light. These sensors consist of millions of photocells, each photocell representing one pixel. When light hits the sensor, each photocell measures the intensity of the light and converts that information into digital data that makes up the final image.

Print size
The number of pixels also affects how large an image can become without losing quality. Printing high-quality photos requires a high resolution, as more pixels allow for better detail reproduction at larger print sizes. In principle, we can print a high-quality A4 photo with a resolution of 2500 x 3500 pixels (about 8 mega-pixels). Modern cameras therefore enable the printing of photos as large as 40 x 50 cm.


Practical use and choice

When choosing a digital camera, it is important to consider the purpose for which you will use the images. Cameras with several mega-pixels (millions of pixels) are suitable for professional use and printing large photos, while a camera with a lower resolution is sufficient for everyday use and sharing online.

Understanding the role and importance of pixels in digital photography helps you make informed decisions when choosing a camera and post-processing your photos. The quality of the final photo depends on many factors, but pixels are the basic unit that determines its basic resolution and detail. However, we should not be fooled by the number of pixels alone, because a lot depends on the quality and size of the lenses, as well as on the physical size of the pixels themselves. With a phone, where we have the possibility of even a 100 mega-pixel image, we will never take such a quality photo as with a camera that only has a third of these pixels (30).


Tomaž Berčič