What is Exposure ?

                        

 Exposure is about much more than the quantity of the light. It is more related to the quality of image such as the nose levels, overall contrast, the details in shadows and highlights, color saturation, and so on. Right exposure will always give the best image for the given conditions.

Elements Exposure 

> Amount of light 

> Reflectance of the objects 

> Lens aperture (iris); diameter of the opening that lets in light 

> Shutter speed; longer shutter speed lets in more light on the sensor 

> Shutter angle; narrower angle causes less light to reach the sensor 

> ISO (sensitivity); Higher ISO can improve brightness, but induces more noise

Aperture

 Most lenses control the quantity of light falling on the camera sensor. This is called the lens aperture and it is measured in f/stops. On the lens, the f/stop is the ratio of the lens focal length to the diameter of the entrance pupil. Opening up one stop means twice as much light is passing through the iris.

 F/stops are not only applied to lenses, but frequently used in lighting as well.

Shutter Speed

 Film cameras have shutters that rotate to either allow light to reach the recording medium or completely close off the light. If the camera runs at a very low frame rate (such as 5 FPS), then each frame will get more exposure time. However, at higher frame rates (120 FPS), each frame will be exposed to light for a much shorter period of time.

Under exposure 

The brightness values of the scene highlights are recorded as medium or just light tones. The shadows  moved to an area downside where there is no separation or detail recorded .

Over exposure

The brightness values of the scene are high. The darker areas of the scene are recorded in gray. The scene highlights on the right side have no detail or separation. Increasing the exposure in this flat part does not modify the image. This results in loss of detail and separation.

Correct Exposure

Observe that how the correct exposure values are placed. The correct amount of light ray adjustment.

Exposure depend on how much light source and the quality of light that comes to the image. Adjust the exposure value before you click the picture.