AS ISO 1223 pdf download

AS ISO 1223 pdf download.Photography — Digital still cameras — Determination of exposure index, ISO speed ratings, standard output sensitivity, and recommended exposure index
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .iso .org/ obp — IEC Electropedia: available at http:// www .electropedia .org/ 3.1 digital still camera DSC device which incorporates an image sensor and which produces digital image data representing a still picture Note 1 to entry: A digital still camera is typically a portable, hand-held device. The device can provide additional functions, for example video image capture or wireless telephony. The digital image data is usually recorded on a removable memory, such as a solid-state memory card or using internal memory. 3.2 DSC image signal image data stored or output by a digital still camera 3.3 exposure index EI numerical value that is inversely proportional to the exposure provided to an image sensor to obtain an image Note 1 to entry: Images obtained from a DSC using a range of exposure index values will normally provide a range of image quality levels.3.4 exposure saturation minimum focal plane exposure that produces the maximum valid (not clipped or bloomed) DSC image signal Note 1 to entry: The exposure saturation is expressed in lux-seconds (lx·s). 3.5 exposure series series of images of the same subject taken using different exposure index values 3.6 image sensor electronic device that converts incident electromagnetic radiation into an electronic signal EXAMPLE A charge coupled device (CCD) array or a CMOS image array. 3.7 ISO speed numerical value calculated from the exposure provided at the focal plane of a DSC to produce specified DSC image signal characteristics Note 1 to entry: The ISO speed is usually the highest exposure index value that still provides peak image quality for normal scenes. However, a DSC does not necessarily use the ISO speed value as the exposure index value when capturing images. 3.8 ISO speed latitude set of two numerical values calculated from the exposure provided at the focal plane of a DSC to produce specified DSC image signal characteristics Note 1 to entry: The ISO speed latitude is expected to correlate with the range of exposure index values that provide acceptable image quality for normal scenes. 3.9 photographic sensitivity general term used for numerical values calculated based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index Note 1 to entry: In practise, the photographic sensitivity is often called the “sensitivity” or the “camera sensitivity”. It is sometimes called the “ISO sensitivity”, for historical reasons that date from ISO standards for photographic film cameras.3.10 photosite integration time total time period during which the photosites of an image sensor are able to integrate the light from the scene to form an image 3.11 recommended exposure index REI specific exposure index value recommended by a DSC provider as a reference for adjusting photographic accessories Note 1 to entry: REI provides a practical exposure index value for setting the reference exposure index of light meters, studio lighting, etc., but images taken using this exposure index value do not necessarily provide the best image quality.3.12 signal processing operations performed by electronic circuits or algorithms that convert or modify the output of an image sensor 3.13 sensitivity setting numerical value of the photographic sensitivity used by a DSC when capturing images Note 1 to entry: In some cases the sensitivity setting is set by the user. In other cases it is set automatically by the DSC. Note 2 to entry: In DSCs employing an automatic exposure control system, the difference between the EI value used to capture an image and the sensitivity setting is called the “exposure bias”. The value of the exposure bias is typically indicated using EV (exposure value) units. Note 3 to entry: For historical reasons, the sensitivity setting of a DSC is often labelled the “ISO”. 3.14 standard output sensitivity SOS specific exposure index value for a DSC that provides a still image with a specified DSC image signal value under specified test conditions Note 1 to entry: SOS provides a practical exposure index value based on the signal level of images captured with a DSC, but images taken using this exposure index value do not necessarily provide the best image quality.