标准摘要
[中文适用范围]： ISO 517:2008 适用于影响图像中心照度的摄影镜头的光圈和相关属性。 ISO 517:2008 规定了静态相机中使用的所有类型镜头的光圈标记，并给出了光圈数的公差。 它还定义了孔径光阑、入射光瞳、焦距、相对孔径和光阑数，并给出了它们的测量或确定方法。 ISO 517:2008 仅适用于聚焦于无限远物体的镜头；即至少为镜头焦距的 50 倍。 [外文原描述]： ISO 517:2008 pertains to apertures and related properties of photographic lenses affecting the illuminance at the centre of the image. ISO 517:2008 specifies aperture markings for all types of lenses used in still cameras, and gives tolerances for the stop numbers. It also defines aperture stop, entrance pupil, focal length, relative aperture and stop numbers, and gives methods for their measurement or determination. ISO 517:2008 applies only to lenses focused on objects at infinity; that is, at least 50 times the focal length of the lens.
英文名称Photography — Apertures and related properties pertaining to photographic lenses — Designations and measurements