Appendix 1: Measuring Light Levels with a Camera
- 35 millimetre camera with a built-in light meter; and
- white cardboard (about 30 - 40 square centimetres).
- place the cardboard in the same position and at the same angle as the object or area that is being measured;
- set the camera to 800 ASA and without casting a shadow on the white cardboard, take an f-stop and shutter speed reading with the camera;
- the cardboard should fill the frame in the viewfinder of the camera; and
- use the coordinates obtained to determine the light level using the table shown below (for example, f8 at 1/30 sec = 700 lux).
|Shutter speed in seconds|
The values quoted in the table were obtained using a Gossen Lunasix 3 light meter, cross referenced with a range of Nikon cameras. Regard the readings as approximations only.