Basic of camera

There are several parts, shutter speed, ISO, apture, focus point,  that will control the final image.

Shutter Speed:

In photography, shutter speed is the common term for exposure time, the length of time a shutter is open, or lenght  of how much light reaching the  image sensor. Factors that affect the total exposure of a photograph include the scene luminance, the aperture size (f-number), and the exposure time (shutter speed); photographers can trade off shutter speed and aperture by using units of stops.

(Copyrighted from How Stuff works)

Different shutter speed effects (Copyrighted from How Stuff works)

Focus point:

Due to the optical properties of camera Lenses, only objects within a limited range of distances from the camera will be appeared clearly. The process of adjusting this range is known as changing the camera’s focus. There are various ways of focusing a camera accurately. The simplest cameras have fixed focus and use a small aperture and wide-angle lens to ensure that everything within a certain range of distance from the lens, usually around 3 metres (10 ft) to infinity, is in reasonable focus.

Different focus point in a digital camera (Photography For Dummies, 2nd Edition )

Camera’s ISO:

ISO sensitivity expresses the amount of how sensitivity of this censor  (formerly expressed as ASA).Since digital cameras do not use film but use image sensors instead, the ISO equivalent is usually given.What ISO number is how sensitive the image sensor is to the amount of light present. The higher the ISO, the more sensitive the image sensor and therefore the possibility to take pictures in low-light situations.ISO speed affects the shutter speed / aperture combinations you can use to obtain correct exposure.Suppose your digital camera’s light meter warns you there is not enough light to correctly expose a scene. You could use the on-board flash, but let’s suppose again it’s not allowed (like in a concert or indoors recital).You would then need to use a higher ISO. Set on “ISO Auto” mode, your digital camera will automatically select a higher ISO. Otherwise, you can manually select the next higher ISO and see if the increased sensitivity allows you to obtain a correctly exposed picture. If it does, you can now take a correctly exposed picture.

Different ISO effect

Camera Aperture :

To control the film’s exposure to light, your picture will come out dark or too bright. There are  two major factors to control:

• How much light is passing through the lens( F-stop)
• How long the film is exposed( shutter speed)

The main function of a lens is control how much the light is passing through. The aperture of a lens is the diameter of the lens opening .The larger the diameter of the aperture, the more light reaches the image sensor.Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture).

The comparison of different F-stop effect(Copyrighted By Liz Masoner, About.com)

Finally, a picture collection of great photographer: