## What does a flash meter do?

A flash meter reads the level of an electronic flash assuming the short duration will be used in its entirety to take a picture and will ignore the continuous, ambient light.

What is the flash guide number?

Guide Number (GN) is a numerical method used to determine exposure of direct flash for Manual flash power levels, to automatically deal with the Inverse Square Law, making the math be trivial.

What is 2/3 of a stop?

The fraction 1/3 stop is 0.333 stops, and 2/3 stop is 0.667 stops, so a reading of 3/10 is around one third stop, and one of 7/10 is about two third stops. The camera can only be set to third stops, so just pick the nearest third stop: 0, 1/3, 2/3, or 1 stop. This is just a more precise exposure reading.

### What is a light meter called?

exposure meter, also called light meter, photographic auxiliary device that measures the intensity of light and indicates proper exposure (i.e., the combination of aperture and shutter speed) for film or image sensors of a specific sensitivity.

Why do we need a light meter?

Light Meters can measure the amount of light falling on a subject (incident light), or being reflected by a subject (reflective light). By converting these measurements, it defines what would be the most beneficial shutter speed and f/stop to use for that given subject.

What does flash coverage mean?

The angle of coverage, also known as the flash angle, refers to the area that the light from a flash can cover in terms of the lens angle-of-view (focal length). Built-in flashes have an angle of coverage designed to cover an angle-of-view equivalent to the wide-end of a standard zoom lens.

#### How is flash output measured?

GN = Subject Distance from Flash Source x f/Stop Guide numbers are based on a simple mathematical equation that states: the light output of an electronic flash is equal to the distance of the flash unit from the subject multiplied by the lens aperture, or f/stop.

What is one full f-stop?

Full stop numbers are f/1.8, f/2.8, f/4/0, f/5.6, f/8.0, f/11, f/16, f/22, f/32, f/64. They are called “full stops” because when you change the aperture from f/11 to f/8.0 that doubles the amount of light. Every time you go up one stop f/5.6 -> f/4.0, you double the amount of light that gets through the lens.