The improved flash was introduced in 1970 as the Vivitar 283 outselling all its competitors combined and selling 3,000,000 units by 1973 .
283 quickly became the number one professional and enthusiast flash unit .
The improved flash was introduced in 1970 as the Vivitar 283 , which quickly became the number one professional and enthusiast flash unit , outselling all its competitors combined and selling 3,000,000 units by 1973 .