There are several camera related classes which can be used to access images and videos from mobile device cameras or webcams. The following information is a brief overview of the camera components.

Lens Assembly

At one end of the camera assembly is the lens assembly (one or more lenses, arranged to focus light onto the sensor). The lenses themselves can sometimes be moved to adjust things like focus and zoom, or they might be fixed in an arrangement to give a good balance between objects in focus, and cost.

Some lens assemblies can automatically be adjusted so that an object at different distances from the camera can be kept in focus. This is usually done by measuring how sharp a particular area of the frame is, and by adjusting the lens assembly until it is maximally sharp. In some cases the camera will always use the center of the frame for this. Other cameras may also allow the region to focus to be specified (for "touch to zoom", or "face zoom" features).

Sensor

Once light arrives at the sensor, it gets converted into digital pixels. This process can depend on a number of things but ultimately comes down to two things - how long the conversion is allowed to take, and how bright the light is. The longer a conversion can take, the better the quality. Using a flash can assist with letting more light hit the sensor, allowing it to convert pixels faster, giving better quality for the same amount of time. Conversely, allowing a longer conversion time can let you take photos in darker environments, as long as the camera is steady.

Image Processing

After the image has been captured by the sensor, the camera firmware performs various image processing tasks on it to compensate for various sensor characteristics, current lighting, and desired image properties. Faster sensor pixel conversion times tend to introduce digital noise, so some amount of image processing can be done to remove this based on the camera sensor settings.

The color of the image can also be adjusted at this stage to compensate for different light sources - fluorescent lights and sunlight give very different appearances to the same object, so the image can be adjusted based on the white balance of the picture (due to the different color temperatures of the light sources).

Some forms of "special effects" can also be performed at this stage. Black and white, sepia, or "negative" style images can be produced.

Recording an Image

Finally, once a perfectly focused, exposed and processed image has been created, it can be put to good use. Camera images can be further processed by application code (for example, to detect barcodes, or to stitch together a panoramic image), or saved to a common format like JPEG, or used to create a movie. Many of these tasks have classes to assist them.