Camera Exposure

• The lighting of an image, how dark or light it it, depends on how much exposure the photograph had experienced. 
• The exposure of an imagine is determined by the exposure triangle, aperture, ISO and shutter speed.
•  Aperture controls the area over which light can enter your camera, shutter speed controls the duration of the exposure and ISO speed controls the sensitivity of your camera's sensor to a given amount of light.
•  Using many combinations of the three settings can achieve the same exposure, the key is to know which trade-offs to make. You need to know that aperture affects the depth of field, shutter speed  affects the motion of the blur and ISO speed affects image noise.
•  The shutter speeds specifically refers to how long this light is permitted to enter the camera, a faster shutter mean a shorter exposure time.
•  A camera's aperture setting controls the area over which light can pass through your camera lens.
• An f-stop value can be counter-intuitive because the opening increases as the f-stop value decreases.
• A camera's aperture setting is what determines a photo's depth of field
• ISO speed determines how sensitive the camera is to incoming light
• Unlike aperture and shutter speed, the lower ISO speed is usually always desirable
• In Auto Exposure the Camera automatically selects all exposure settings.
• In Program the camera automatically selects aperture & shutter speed; you can choose a corresponding ISO speed & exposure compensation. 
• In Aperture Priority you specify the aperture & ISO; the camera's metering determines the corresponding shutter speed.
• In Shutter priority you specify the shutter speed & ISO; the camera's metering determines the corresponding aperture.
• In Manual you specify the aperture, ISO and shutter speed — regardless of whether these values lead to a correct exposure.
• Bulb is useful for exposures longer than 30 seconds.
• In Portrait the Camera tries to pick the lowest f-stop value possible for a given exposure.
• In Landscape the Camera tries to pick a high f-stop to ensure a large depth of field. 
• In Sports/Action the Camera tries to achieve as fast a shutter speed as possible for a given exposure
• In Night/Low-light the Camera permits shutter speeds which are longer than ordinarily allowed for hand-held shots