EXIF (Exchangeable image file format) is a standard of metadata information used by cameras and other imaging and audio devices like scanners and recorders.
EXIF data in images captured with digital cameras and smart phones contains information on camera settings including type of the camera and lens, focal length, aperture, white balance, presence of a flash, picture mode etc. Devices equipped with GPS receivers, like most smart phones, can also store location information.
EXIF information can be stored in both standard image files like JPEG and RAW images produced by DSLRs.
In addition to standard fields most camera makers define custom extensions referred to as maker notes.
Histogram is a chart that presents a distribution of values. A photo histogram typically displays distribution of brightness and/or red, green and blue color channels.