ISO Voltage August 18, 2021 at 10:34 am

Devices are used as main light source, and additional (eg, to illuminate the shadows in backlit and etc.). The basic units of devices: pulsed light source – discharge lamp, filled with an inert gas, usually xenon: lamp ignition device, consisting of step-up transformer and auxiliary components: storage of electrical energy – large capacitors, the device power supply – battery galvanic cell or battery current converter, a device for connecting to an electrical outlet or to another power source. Filed under: Roger Goodell. Nodes are merged into a single structure consisting of a body with a reflector, or arranged in two blocks or more. More convenient pulse flash, battery powered flashlight, batteries 373 and etc. Their main advantage – the autonomy of power. As an independent power supply can be used and batteries. They free the photographer from the frequent change of batteries are depleted. A number of converters voltage has an automatic device to turn on (when charging or charging a capacitor) and off (when the operating voltage on the capacitor) supply.

Electronic pulse flash FIL-PM, "Electron" and several others are equipped with transducers on transistors, "Light," photon "and some others can be fed to the inverter type PN-70. In pulsed flash previous releases electromechanical voltage converters, but they are less reliable and create increased noise at work. Flashlights PHIL-9. Zarya differ from those devices that they do not have storage capacitors. Wide dissemination of these flash units is not received, as they work only on ac power, have low stability of the energy of flares and other shortcomings. Flash energy depends on the capacity and voltage storage capacitor. Flash energy can be controlled by varying the total capacitance of the capacitor with a special switch.

Energy may be reduced by lowering the supply voltage due to discharge Batteries, – is the product of the distance from flash to the subject by the number of the lens aperture. The guide number depends on the flare energy, scattering angle of the light beam and reflector design. Usually guide number is indicated for the film sensitivity of 65 units. gost, more rarely to others. (In modern outbreaks guide number is indicated for the film sensitivity of 100 ISO) If the subject is light (white), then the number of aperture increase for more than a dark object reduces the number of diaphragms. Furthermore, the actual values of energy and leading numbers may differ slightly from those indicated in the passport of the flash. The reason there are deviations of capacity capacitors within their tolerances, changes in voltage and other factors, in most cases, these deviations are minor and can not be taken into account. If the exposure should be more accurate, should clarify the guide number for a test shoot.

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