page_title: Exposure (photography)
section_title: Exposure control
hierarchical_section_title: Exposure (photography) / Exposure control
caption_attribution_description: English: Fountain at Kew Gardens, England, with a 1/30s exposure timeThis is a photo of listed building number 1262672.
context_page_description: In photography, exposure is the amount of light per unit area reaching a frame of photographic film or the surface of an electronic image sensor, as determined by shutter speed, lens aperture, and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value and scene luminance in a specified region.
  An "exposure" is a single shutter cycle. For example, a long exposure refers to a single, long shutter cycle to gather enough dim light, whereas a multiple exposure involves a series of shutter cycles, effectively layering a series of photographs in one image. The accumulated photometric exposure is the same so long as the total exposure time is the same.
context_section_description: An appropriate exposure for a photograph is determined by the sensitivity of the medium used.  For photographic film, sensitivity is referred to as film speed and is measured on a scale published by the International Organization for Standardization (ISO). Faster film, that is, film with a higher ISO rating, requires less exposure to make a readable image. Digital cameras usually have variable ISO settings that provide additional flexibility.  Exposure is a combination of the length of time and the illuminance at the photosensitive material. Exposure time is controlled in a camera by shutter speed, and the illuminance depends on the lens aperture and the scene luminance. Slower shutter speeds (exposing the medium for a longer period of time), greater lens apertures (admitting more light), and higher-luminance scenes produce greater exposures.
  An approximately correct exposure will be obtained on a sunny day using ISO 100 film, an aperture of f/16 and a shutter speed of 1/100 of a second. This is called the sunny 16 rule: at an aperture of f/16 on a sunny day, a suitable shutter speed will be one over the film speed (or closest equivalent).
  A scene can be exposed in many ways, depending on the desired effect a photographer wishes to convey.
caption: A 1/30 s exposure showing motion blur on fountain at Royal Botanic Gardens, Kew
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 5D Mark II", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2009:08:01 11:52:27", "Image ExifOffset": "173", "EXIF ExposureTime": "1/30", "EXIF FNumber": "10", "EXIF ExposureProgram": "Shutter Priority", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2009:08:01 11:52:27", "EXIF DateTimeDigitized": "2009:08:01 11:52:27", "EXIF ShutterSpeedValue": "5", "EXIF ApertureValue": "53/8", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Spot", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "170", "EXIF SubSecTime": "54", "EXIF SubSecTimeOriginal": "54", "EXIF SubSecTimeDigitized": "54", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "5616", "EXIF ExifImageLength": "3744", "EXIF FocalPlaneXResolution": "200159/52", "EXIF FocalPlaneYResolution": "551048/141", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard"}