For those that wish to take their photography to the next level, an off camera light meter will be required at some point. The in-camera light meters are fairly sophisticated these days, but you are still locked into the camera body with many limitations. Professional photographers – both studio and onsite – use specialist light meters that are more suitable for their work.
The following article deals with the terminology you will come across when researching light meters, measurement and conditions.
definition:a device that measures the light available and has a computer that calculates an exposure based on light intensity and film speed or ISO.
There are two styles of light meters:
An incident meter measures light falling on the subject before the camera. This meter is hand held and is separate from the camera.
This meter measures light reflected from the subject. This meter may also be hand held and is often an integral part of the camera.
Many light meters on the market today offer both systems in a single light meter. You can also purchase professional specialist meters in one unit.
Interpreting Light (definitions)
Pre-visualisation is the act of observing a scene with the physical eye and seeing in the mind’s eye how a medium can render the subject.
This may be aligned to the photographer’s creativity.
A ‘Zone’ is a visual unit of measurement for luminance. It is arrived at by altering the standard exposure of a light meter by one stop more or one stop less.
3. Luminance Meters
Luminance meters are useful for pre-visualisation, they measure light reflected from surfaces and carry various scales by which exposures are indicated.
4. Value Scale
The term ‘value’ refers to the degree of lightness and darkness of a colour. In a photographic print the display of greys or values is known as the scale.
To aid pre-visualisation the continuous value scale is arbitrarily divided into nine steps.
5. Value Rendering
The term rendering is used rather than recording because photographs are generally gross approximations of the actual values found in the originals.
Rendering suggests that there may be a choice among possibilities of interpretations. Value rendering is planned and pre-visualised in tones.
6. Zone System
With pre-visualisation and value rendering, a system is developed to allow the photographer to:
1. Translate subject values into print values.
2. Resolve problems to provide the best photographic interpretation of a real object.
3. In viewing and processing, complete image plans before an exposure is made.