Exposure measuring method

You may wondering that how camera measure the light or exposure;
the camera�s exposure sensor = an exposure meter

To measure the exposure is very important thing for your shot because it tell you the amount of light is needed to adequately expose your picture. So it is important to have the knowledge about this thing!

3 Types of Measuring the light:

Center-Weighted Meters
In the old days, most cameras came with a simple center-weighted light meter. This meter measures the light overall the image but take the more intense on the center of the frame you see in the view-finder.
We can say that usually it is a great one that you are most interested in the stuff in the front of the picture, Also you can the below picture for the example of this type of measuring.

Matrix Meters (Invented by Nikon)
This system is most prevalent in Nikon models, all the way from the CoolPix 950 and CoolPix 995 to the high-end D1x. The matrix meter by add more intense of light not only at the center but also intense on all of the 4 corners within a picture. Matrix meters gauge the light in many parts of the scene at once. Many people say that this type of measuring is the best for you to setting this mode all the time.

Spot Meters
As you know the meaning of spot; Spot is the specific point or may be part from whole picture. The spot meter is the optional for you if you do not want to use the centre weight or matrix meter As you can see below picture:

It will concentrate only on the center and ignore the rest of the frame completely. This make the ways to use this meter is not often also to measure only one persent of light from feull frame normally give the poor but a meter that only measured the light in the central one percent of the full frame would typically take not so good pictures

Besides, under or overexposed depending on the situation.

So when should you use the spot meter?
I think that you use this technic when you want to focus on a small subject that must be outstanding property from other and also the light at it is much difference from other (one precise point of the image). For example, if you want to take the picture of the person ware brown suit that is stand in front of a brightly lit window, if you let the camera define exposure the bright light from the window will underexpose the subject so you should switch on the spot meter and expose the picture based on the subject. YES you may say that, the window light will be overexposed, but It�s ok because the important point of this picture is the person.