November 7, 2025, 11:55 am | Read time: 3 minutes
Megapixels are a crucial measurement unit for smartphone cameras. More megapixels promise better image quality. But is that really true?
Smartphones are handy helpers in almost every daily life. Making calls, surfing the internet, taking photos–all combined in one device. For many, the smartphone has long replaced the digital camera for photography. That’s why the quality of the camera is an important factor when buying. One of the first features many people look at when choosing is the number of megapixels in the camera. The common assumption is that more megapixels mean a better picture. TECHBOOK explains the technical background and whether that’s really true.
Why are megapixels needed in smartphone cameras?
For years, there’s been a trend in smartphone cameras to have more and more megapixels. Nowadays, 200 megapixels are not uncommon in flagship devices, as well as in lower price segments. For example, the Samsung Galaxy S23 Ultra has such a camera, as do the Xiaomi Redmi Note 13 Pro and the Motorola Edge 30 Ultra. But what exactly are megapixels?
A megapixel means one million pixels. This corresponds to a square image with a height and width of 1024 pixels each. The more pixels an image has, the denser and sharper it becomes, as the resolution improves.
So, more megapixels mean a more detailed and therefore better image–or do they? It’s not that simple. Numerous cases prove that smartphones with a lower megapixel count can take better quality photos than models with a higher count.
Sensor size determines image quality
It’s not just the pixels that count. The size of the sensor is crucial for the image quality of a photo. The sensor is responsible for capturing incoming light and converting it into a digital signal. The larger a pixel is, the lower the megapixel count, but the sensor is correspondingly larger. A larger sensor means more captured light, which in turn reduces image noise. Conversely, a smaller sensor leads to more image noise because the individual pixels have less space.
Read more: What makes a good smartphone camera
These proportions are mainly due to the limited space in the housing. A smartphone has to accommodate much more than just the camera. There comes a point where more megapixels no longer lead to better photos because the pixels on the sensor become too small. Thus, the image quality remains the same or even worsens despite high resolution.
In cameras, the number of pixels and the sensor size are better matched. That’s why SLR cameras with a larger sensor and the same number of megapixels produce sharper and more vibrant images than an iPhone with the same resolution.
With information from dpa.