21. The light meter used a dual-concentric segmented silicon photo-diode to provide spot or centerweighted readings. 22. Most modern light meters use silicon or CdS sensors. 23. The light meter used a dual-concentric segmented silicon photodiode to provide spot or center-weighted readings. 24. The most common use of such light meters is measuring the exposure value for photography. 25. A light meter can automatically calculate the ratio of key plus fill to fill alone. 26. Prior to this, TTL metering required a special prism viewfinder with a built-in light meter . 27. It offered numerous improvements over the older model including an integrated rangefinder and coupled light meter . 28. Later models, such as the Baldessa 1b, introduced a coupled rangefinder and inbuilt selenium light meter . 29. Magubane pulled out his light meter : " When he started talking, I opened the back. 30. Built-in light meters and electronic shutters combined with microelectronics to make exposure control simpler and faster.
