Understanding camera features - Megapixels

I hope the Camera Types post on this blog allowed you to decide what kind of photographer you would like to be and then decide what type of camera you were looking for.

However, if you step into a camera shop and ask the salesperson to show you some cameras, unless you specify your requirements, chances are 9 out of 10 that he will first tell you about the MP or the Megapixel count.

So one would say, bigger or higher Megapixel is always better, right??

Well…. not always! Before we get to answering that question, lets see what exactly a pixel is. A pixel is a portmanteau of the words Picture and Cell. So the word pixel means one cell or one unit of the digital picture. See the picture below for some clarity:

At a large magnification, the cute kitty on the left is actually composed of many many little squares which form the complete picture. Each square can have only one single colour, but the number of colours available to each little square to paint himself or herself is a range of 16 million colours!!!

So all these little pixels, arranged in rows upon rows make up the complete picture. The number of pixels in the area of the picture make up the picture’s pixel count. The pixel count is like the tiles on a room floor. If you have a room that is 20 feet long and 10 feet wide, and the tiles are 1 feet square, you will need 20 x 10 = 200 tiles to cover the whole room.

Similarly the picture of the cat above is 350 pixels tall and 350 pixels wide. So the number of pixels in the picture or the pixel count of the picture is 360 x 360 = 122600 pixels. That’s 122600 little coloured squares that make up that picture.

A Megapixel is nothing but a collection of 1000000 pixels. Thus if you divide any pixel count by 1 million, you get the Megapixel count. So the Megapixel count of the above kitty is 122600 ÷ 1000000 = 0.1226 megapixels.

Wow, that was a lot of math up there. But do not worry. You don’t have to carry a calculator with your camera when you take pictures.

What does the megapixel count indicate

As I said, the number of megapixels actually lets you know the area of the picture you would be taking. So larger the Megapixel size, bigger the picture area.

Max Print Size	Typical Use	Minimum MP	Resolution
4 x 6″	- Photo Albums	2 megapixels	1600 x 1200
5 x 7”	- Photo Frames	3 megapixels	2048 x 1536
8 x1 0″	- Large Photo Frames	5 megapixels	2560 x 1920
11 x 14″	- Commercial Prints - Wallpaper	6 megapixels	2816 x 2112
16 x 20″	- Wallpaper - Hoarding Posters	8+ megapixels	3264 x 2468

The megapixel rating of a camera is the number of pixels on its photo sensor, the “film” or recording medium of the digital camera. The ability of the camera to record more pixels actually means that the camera can capture more of the image. This essentially translates into more detail in the picture.

So that more detail is supposed to be better, right??

Well, it depends. The detail that is captured on the camera’s sensor is only useful for the size of the print. When a high detail picture is resized to a small area, it is a sharp picture but the extra detail does not really add to the view. I took the picture below from my terrace. It is a 3 Megapixel picture.

The picture on the top is a small part of the larger picture at its real size. Notice the detail of the creek and the little cranes on the edge of the creek.

 

Now here is the whole photograph, resized to a smaller size to post on the blog. Notice the same creek but now the cranes are small specks. While the detail is there in both photographs [They’re the same photo], at a smaller size, the extra detail is insignificant. The same would happen if you clicked a 12 megapixel photograph and then got it printed to a 4” x 7” size to put in the photo album. 

Another important thing about large megapixel photographs is that the larger the megapixel size, the larger the size of the photo. a 5 MP photo is roughly about 2 Megabytes in size. While that’s not too big, going on a vacation with only a 4GB storage card in your camera and clicking high resolution 12 Megapixel photos will fill up your card very very quickly, while all you wanted to do was bring back some memories for a photo album.

In conclusion, while a large megapixel recording camera is good to have, when you look for a camera, keep in mind what you are going to photograph for?? For a photo album or the large frame in your office lobby or the large poster on the side of a apartment building?? If you did read my post on Camera types, here’s a recommendation:

Point and shoot cameras for shooting family occasions, portraits and scenery: 3 – 5 megapixel

Prosumer fixed lens cameras for amateur experimentative photography:  5 – 10 megapixel

dSLR cameras for experienced and commercial photographers: 12+ megapixel

Remember, you can buy bigger megapixels, but buying lesser megapixels when you don’t need them can save you quite a tidy sum. Now you do have something to say to that enthusiastic camera salesman.