標準號：DIN ISO 517-2009
中文標準名稱：攝影技術 照相機鏡頭光圈及其相關特性 名稱和測量法
英文標準名稱：Photography - Apertures and related properties pertaining to photographic lenses - Designations and measurements (ISO 517:2008); English version of DIN ISO 517:2009-05
標準類型：A15
發布日期：1999/12/31 12:00:00
實施日期：1999/12/31 12:00:00
中國標準分類號：A15
國際標準分類號：37.040.10
適用范圍：This International Standard pertains to apertures and related properties of photographic lenses affecting theilluminance at the centre of the image.This International Standard specifies aperture markings for all types of lenses used in still cameras, and givestolerances for the stop numbers. It also defines aperture stop, entrance pupil, focal length, relative apertureand stop numbers, and gives methods for their measurement or determination.This International Standard applies only to lenses focused on objects at infinity; that is, at least 50 times thefocal length of the lens.