Exposure is one of the most fundamental aspects of photography, you'll often hear photographers talking about "making exposure" or getting the exposure right. In essence, "exposure" is simply the process of letting light though camera's lens to illuminate the digital sensor and produce an image. Getting the optimum exposure of your photograph relies on balancing three distinct elements.
The three elements that are key to exposure are APERTURE in the lens; the shutter in the camera; and the senstivity to the light of the sensor itself (ISO). Technically there's is no such thing as the RIGHT exposure.........