What megapixel means and how much you need

What does megapixel mean? Are more megapixels always better? How many megapixels do i need? We explain it to you!

What does megapixel mean?

Megapixel the compound word from mega and pixel.

  • Mega: is a prefix and stands for one million (1'000'000).
  • Pixel: or pixel is the smallest displayable unit in an image.

With this definition we can say: 1 megapixel = 1 million pixels/dots in an image. This corresponds to an image of exactly 1000 x 1000 pixels.

Megapixels are used in the recording and display of images. For example, if we want to print an image with 1 megapixel and 300 dpi (dpi explained here), the image is 85 x 85mm. A full HD monitor (2560 x 1440 pixels) could not display this image in full resolution.

Abbreviations Megapixel: MP, Mpx, Mpix or MPixel?

Many companies use a different abbreviation when specifying megapixels, as no uniform abbreviation has yet been established. Thus, all of the following abbreviations are correct: MP , Mpx , Mpix and MPixel .

We use Mpx as an abbreviation because, in our experience, px is the most common abbreviation for pixels.

Are more megapixels (resolution) always better?

No! Many camera manufacturers use megapixel resolution as the most important quality feature of their products, as it is the easiest quality feature to understand. It is by far not the most important thing now that almost every camera has enough resolution for normal use (12Mpx and up). 12 Mpx can display images on the following media with the best quality:

  • Image for photo album (300dpi) up to 25 x 33cm (larger than A4)
  • Poster (100dpi) up to 75 x 100 cm
  • 4k TV/projector

Megapixels only become important if you want to display images on a larger medium or enlarged sections (posters, large posters, professional photo presentations).

How many megapixels do I really need now?

Correctly recognized, it depends on the application. Let's go over some use cases:

- Display a picture on the internet/blog

If we assume that the image should only be displayed on the Internet, we actually only need a very small number of megapixels, mainly because of the file size that should be as small as possible on the Internet. The images on this blog are displayed with a maximum width of 720 pixels. So I reduce a large picture so that it is exactly 720 pixels wide.

The following picture has a resolution of 720 x 480 pixels and would only require a 0.35 Mpx camera.

MegaPixel MPixel Full HD

- Show the section of a picture in the internet/blog

But if we want to display a section of the image from above in the same quality (720 x 480 pixels), the original image must be a lot larger. The original (above) of the following picture should have a camera resolution of 12 Mpx:

MegaPixel MP CROP

- Calculation of the resolution for further use cases

The resolution is always calculated based on the image size and quality for the application. The quality is the point density (dpi, dots per inch). You can use the following guidelines:

Physical pressure:

  • Photo for photo album: 300 dpi
  • Poster: 100-150 dpi

Presentation on a digital medium (television/monitor/projector)

  • HD: 1280 × 720 pixels ~ 1 Mpx
  • Full HD: 1920 x 1080 pixels ~ 2 Mpx
  • 2K: 2560 x 1440 pixels ~ 4 Mpx
  • 4k: 3840 x 2160 pixels ~ 8 Mpx

You are welcome to use our pixel calculator to calculate other resolutions: Pixel calculator

Why is 1 Mpx specified with 1024 x 1024 pixels (e.g. Wikipedia)

The reason why many camera manufacturers actually calculate 1 megapixel at 1024 x 1024 as the basis for the MP calculation lies in the architecture and manufacture of the sensors. A camera sensor is divided into fixed blocks, each of which ranges from 16 pixels up to 256 pixels in steps of 16 pixels, 64 being a standard value.

Example:

If I had a camera with a width of 1000 pixels, divided into 16-pixel blocks of the sensor, this would result in an odd number of 62.5 blocks. That is not technically possible.

So I build the camera with e.g. 62 blocks or 63 blocks.

  • With 62 blocks of 16 pixels each this results in 992 pixels
  • With 63 blocks of 16 pixels each, this results in 1008 pixels
  • With 64 blocks of 16 pixels each this results in 1024 pixels

Since reading out in 64-pixel blocks is faster today, 16 blocks of 64 pixels each are built in. This then results in the number of 1024 pixels, which is rounded down to 1000 pixels for sales purposes.