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Flash (photography)

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A flash is a device used in photography to produce a brief burst of light. This burst typically lasts about 1/1000 of a second. The primary purpose of a flash is to illuminate a dark scene. It can also capture quickly moving objects or change the quality of light.

Modern cameras often activate these units automatically. Some units are built directly into the camera body. Other cameras use a standardized accessory mount called a hot shoe to attach separate units. Professional studios use large, standalone units or studio strobes. These are powered by special battery packs or connected to mains power.

Flash - Speedlight - SLR Flash - Studio picture 2011
Flash - Speedlight - SLR Flash - Studio picture 2011

To understand how electronic flash works, we must look at its internal mechanism. An electronic flash unit uses circuitry to charge a high-capacitance capacitor. A capacitor is a component that stores electrical energy. This energy is charged to several hundred volts. When the camera's shutter synchronization contact is triggered, the capacitor discharges rapidly. This discharge happens through a permanent flash tube. This process creates an immediate flash that is shorter than most shutter speeds. Because the light reaches full brightness before the shutter even begins to close, photographers can use faster shutter speeds.

The built in flash of a SLR camera, Pentax MZ-30, firing 1
The built in flash of a SLR camera, Pentax MZ-30, firing 1

Flash technology has evolved through several distinct stages. The earliest methods used flammable powders or magnesium ribbons. In 1887, German inventors Adolf Miethe and Johannes Gaedicke introduced flash powder. This was a mixture of magnesium powder and potassium chlorate. Photographers put a measured amount into a pan and ignited it by hand. This produced a brilliant flash, but also created smoke and noise.

AHA Blitzlichtpulverlampe
AHA Blitzlichtpulverlampe

Later, magnesium ribbon became popular. Edward Sonstadt and the Manchester Magnesium Company produced flat magnesium ribbon. This ribbon burned more consistently than round wire. William Mather also invented a holder to burn the ribbon in a lamp.

1909 Victor Flash Lamp
1909 Victor Flash Lamp

Flashbulbs represented a major technological advancement over open powder. These were glass bulbs filled with oxygen gas and a magnesium filament. They were electrically ignited by a contact in the camera shutter. Commercial flashbulbs were first produced in Germany in 1929. These bulbs were single-use and became very hot immediately after use. To improve safety, manufacturers eventually coated bulbs with a plastic film. A blue plastic film was sometimes used to match the spectral quality of daylight-balanced film. Later, magnesium was replaced by zirconium to create an even brighter flash.

E. Leitz Wetzlar flash - 1
E. Leitz Wetzlar flash - 1

Different bulb designs served many different needs in the mid-20th century. The Press 25 bulb was common for newspapermen and reached a peak output of around one million lumens. The GE Mazda No. 75 was the largest flashbulb ever produced. It was over eight inches long and four inches in girth. It was originally developed for nighttime aerial photography during World War II. Other designs like the all-glass PF1 bulb were introduced in 1954 to reduce costs. The PF1 had a faster ignition time than many other bulbs. This allowed it to be used with X synch shutter speeds below 1/250 of a second.

Flashcube on Kodak Instamatic
Flashcube on Kodak Instamatic

In 1965, Eastman Kodak introduced the Flashcube to simplify photography. A Flashcube was a module containing four expendable flashbulbs. Each bulb was mounted at 90 degrees from the others inside a reflector. The camera's film advance mechanism rotated the cube 90 degrees after every shot. This allowed a user to take four images in rapid succession. Another version called the Magicube used four bulbs but did not require electrical power. Instead, it used cocked wire springs to strike a primer tube. This ignited shredded zirconium foil inside the cube.

Flashcube on Kodak Instamatic
Flashcube on Kodak Instamatic

Modern electronic flash, often called a strobe, changed photography forever. Harold Eugene Edgerton introduced the electronic flash tube in 1931. This technology reaches full brightness almost instantaneously. Edgerton used this speed to capture iconic images, such as a bullet bursting through an apple.

Bullet coming from S&W
Bullet coming from S&W

While early units were large and required heavy lead-acid batteries, they became much more portable. By the early 1970s, amateur electronic flashes were available for less than $100. Today, these systems are used in everything from small built-in camera flashes to professional studio setups. Professional studios often use a modelling light to help photographers see the effect of the flash before they take the picture.

Macrogl Stellat
Macrogl Stellat
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🖼️ Images & Media (13)
File:Macrogl Stellat.jpg
Macrogl Stellat.jpg
High Speed Flash Photography.webmhd.webm
File:1909 Victor Flash Lamp.jpg
1909 Victor Flash Lamp.jpg
File:AHA Blitzlichtpulverlampe.jpg
AHA Blitzlichtpulverlampe.jpg
File:E. Leitz Wetzlar flash - 1.JPG
E. Leitz Wetzlar flash - 1.JPG
File:Flashcube on Kodak Instamatic.jpg
Flashcube on Kodak Instamatic.jpg
File:The built in flash of a SLR camera, Pentax MZ-30, firing 1.jpg
The built in flash of a SLR camera,...
File:Flash - Speedlight - SLR Flash - Studio picture 2011.jpg
Flash - Speedlight - SLR Flash - Studio...
File:Bullet coming from S&W.jpg
Bullet coming from S&W.jpg
File:Wiko Rainbow 4G - Flash LED with SGM3140 LED Driver -5572.jpg
Wiko Rainbow 4G - Flash LED with SGM3140...
File:Fill flash.jpg
Fill flash.jpg
File:Flash-Direct-Indirect.jpg
Flash-Direct-Indirect.jpg

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