BS ISO 516:2019 pdf download – Camera shutters一Timing – General definition and mechanical shutter measurements.
1 Scope This document provides a uniform basis for determining the exposure times for all types of shutters used in still cameras and contains suitable definitions of the terms used. It specifies the exposure-time markings for all types of shutters and their tolerances. The characteristics of all types of mechanical shutters, which are mounted in still cameras and affect the control of exposure, motion-stopping ability and synchronization with a photoflash light source are also defined. The tolerances specified are the target values for the shutter performance that can be expected to give good results. They are not intended for application as a general inspection standard in controlling the performance of mechanical shutters, since tolerances may vary with the feature and price class of camera tested. Test methods are described for routine manufacturing testing and quality control. These test methods require access to the focal plane of the camera and can therefore not be applied to assembled digital still cameras. 2 Normative references There are no normative references in this document. 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 front shutter any shutter in the vicinity of the lens Note 1 to entry: The front shutter can be in front of, behind or between the lens elements and can consist of rotating discs, rotating slats, sliding blades, oscillating blades, etc. Programmed shutters are also included. Note 2 to entry: The common characteristic for the front shutter is that the entire picture area is exposed almost simultaneously. Note 3 to entry: When the shutter and diaphragm are located too far apart, both exposure and shutter speed may vary at different points in the picture area. 3.2 focal-plane shutter any shutter in the vicinity of the focal plane Note 1 to entry: The focal-plane shutter can consist of fixed or variable slit curtains, rotating discs, sliding blades, etc.