When purchasing a digital camera we usually inquire about the megapixels. Lets break the word and at first know about what is pixel. Pixels are points arranged in a grid format on a digital image that can be reproduced in any size as small squares or dots that put together form a picture. Each of these pixels are made up of three color channel. One megapixel is made up of one million pixels that means if you have a 4 mp camera then its picture would be made of 4 million pixels. Now a picture image having more pixels is regarded to be of a higher quality. Besides this a picture is considered to be even more better in quality when there are more pixels contracted in every square inch of the image.
However all these facts may not help to get a better quality picture in some cheap digital camera photos. What matters the most are factors such as -
- The size of a sensor – the larger the better
- The size of each pixels reproduced to the size of the sensor
- Quality of the lens
- Processing of the image
All these contribute to the picture quality or resolution of a picture.
The size of a sensor – the larger the better
A very important part of a digital camera is its sensors that can be called as ‘Digital Film’ because this is the one that captures the light. The light that enters through the camera lens passes through the sensors which are made up of these pixels. A digital camera records a picture by the light coming through the lens into tiny electrical signals. It does this by using millions of tiny light sensitive pixels. Each individual pixel acts as a miniature light magnifier that increases the intensity of light hitting it and converts it into electrical signals. So the brighter the light the greater the electrical signals to record it.
So the main thing to understand about these sensors is the size. A picture taken from a latest 8 or even 10 megapixel compact or a smartphone camera will never look as good as an entry level digital SLR .This is due to the difference in sensor size and therefore the individual pixel size used in both devices
Look into the Sensor sizes.
The full frame sensor size DSLR cameras can cost much higher price than a compact camera with the same pixel count which will cost less.
The size of each pixels reproduced to the size of the Sensor
A question that now arises is how many megapixels should be relative to the size of a sensor this is where pixel density comes in. To explain this let us consider the sensor size of a compact or smartphone camera, as a megapixel war between camera manufactures the easiest solution is to cram in more and more megapixels without enlarging the sensor size because larger sensors are more expensive to make and larger sensors would make cameras larger. More megapixels on the same sensor size actually means that the pixels need to be smaller [to fit more pixels] as the example picture shown below. Generally sensors with smaller pixel size tend to be less efficient; the smaller pixels are less sensitive to light and exhibit more digital noise , this is the graininess you see in a picture when shooting in low light conditions. As DSLR cameras have larger sensors than compact/smartphone cameras this maintains that they can have larger pixels. This means that 8 megapixel DSLR camera is better than a 10 megapixel smartphone camera.
Digital Noise in right picture
The size of a each pixel is measured in Microns. An 8 megapixel Iphone 4S has 1/3.2-inch type sensor while most of the compact cameras have a 1/2.3-inch type sensor. The more megapixel you increase the more the size of sensor can be increased and the bigger the size of sensor more better the picture quality. The latest illuminating sensors used in smartphones at present can give better performance even in low light however they can blow up the picture when the lights are bright.
Quality of the lens
The first component of the camera is the camera Lens. Usually a standard lens of a camera is convex that means the surface of the lens is bend outwards. Different camera lenses can give different effects to a picture. While using a flat and shallow lens you will notice a ‘zoom in’ effect even shooting smaller part of an image, in opposite to this while using a round and deep lens you will get a wide view but the objects will appear smaller.
Digital Processing of the image
Besides taking in account the quality and size of pixels, sensors and lens there is another factor that influences the picture graphics of an image.
This is the camera or smartphone chip – a very important hardware element and software that helps to process the photos and videos.
There are other logical algorithms that create a photo.
The processor of the image also helps – the minimum shutter lapse that is when capturing photo just after you press the capture button.
Ultimately you are king
It is very unfortunate that the camera manufactures don’t share the minor but very important details of the camera components with the customers leaving them confused and ignorant. Much said it is true that if you are planning to own a camera with a good quality sensor and other elements along with large pixel size plus high megapixel count , then it would certainly cost you much higher in price.
But the two relevant points you need to take in are that if you are looking out for a very high quality professional photos that are needed to be cropped and printed in large [more than A4 size] then you do require a high megapixel camera as cropping involves zooming in to a certain portion of an image resulting to which can break the pixels and thus disturb the picture resolution. To this if you are just wanting to click your photos and share them or view them on computer a 5 megapixel camera is perfect.
Now you know that the bigger the senors the more megapixels it can handle and the larger the size of each pixel the better picture quality you get out of it. To fit more megapixels in small sensors the pixels are made smaller leading to no difference in the picture quality and resolution despite increasing the megapixels.