Welcome back! In this post I will continue solving concepts and doubts related to the previous publication. If you haven’t read it yet, you can do it here.

What is a MEGAPIXEL?

1 Megapixel = 1.000.000 pixels. It’s that simple!

Then, when we talk about the MP of a camera, we are referring to the maximum number of pixels our images are able to contain. This means that, for example, a camera with 8 Megapixels can produce photographs up to 8.000.000 pixels.

It doesn’t matter the proportion of the images. It doesn’t matter how pixels are placed in rows and columns. We are just talking about the total number of pixels that our image contains. To be clear, it’s the size of the image in pixels.

It’s a very common mistake to think that, if a camera has more Megapixels, you will get better quality in your photos. Well, this is not true at all. It simply means that you will be able to take bigger photos in size. This can be very useful for printing big pictures or visualizing them on bigger screens.

At this point, it happens to be confused with the term resolution. We tend to think that, if we have a big resolution (size in pixels), we also have high quality images. This is not true, we will only have bigger photos.

Then, Which parameters define the QUALITY of an image?

There are plenty of them: illumination, exposition, color, contrast, compression, lens,… But we can affirm that the most relevant are: the sensor and the processor of the camera.

The sensor of the digital camera is the element that collects the light information that comes from the lens. It’s a chip composed by a grid of photo-sensitive cells. Sounds familiar?

Each cell produces an electrical pulse when they receive the light information. Then, the processor transforms it into a digital sign. Each cell will provide the information able to create 1 pixel of the final image. So, we can say that each cell is a pixel.

Basically, the sensor can be understood as an infinite film roll in analogue cameras.

Photographs are made of light. Consequently, the results will depend on the capability of the sensor. For example, imagine that we have 2 cameras with the same amount of Megapixels and sensor dimensions. We will get better photos with the most “powerful” sensor. Makes sense, right?

In addition, the size of the sensor is really important. It directly affects the size and number of the photo-sensitive cells. Then, a bigger sensor will allow bigger cells. So, if the cells are bigger, they will be able to receive more information from the light, improving the quality of the final image.

As you can see, the sensor size is connected to Megapixels.

Smartphones have very small sensors compared to a reflex camera. This means that, even if both have the same number of megapixels, the reflex camera sensor can reproduce more information in each photograph.

Let’s do it simple! Imagine that we have 2 cameras with the same size and “power” of the sensor. But, we have different megapixels:

  • Camera A= 10 Megapixels: It will produce better quality images since its cells are bigger. The images will have up to 10 million pixels.
  • Camera B= 20 Megapixels: It will produce lower quality images since its cells are smaller for the same sensor surface. The images will have up to 20 million pixels.

So, we will have to decide if we want big images or high quality photographs. Just think about the balance you need. It’s up to you!

Apart from this, the processor is the element that “transforms” the information captured by the sensor. It depends on the CPU and the graphics integrated in the camera for this purpose.

The quality of the final image will be defined by the communication among both, processor and sensor.

That’s all for this week! Next theoretical post will be focused on “resolution” and density of pixels.

Hope you learnt a lot! Thanks for reading! 🙂

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