Hints and Tips on Exposure In this section are a number of suggestions for improving your results when taking pictures or entering into our competitions. If members have any suggestions for tips or would like to submit your own tips, please email them to the webmaster.   There are four elements to exposure. 1.  Light The amount of light available will determine what can be done. There is often three ways of measuring light. • Evaluative Colour Metering is used to evaluate the colours in several areas of the image. • Centre Weighted Metering is used to give priority to the central area of the image. • Spot Metering is used to give priority to just one point of the image. 2.  Aperture The amount of light allowed through will determine the depth of field. Aperture is normally referred to as F stops. The F number is used in calculation of the physical size. Therefore 50mm lens at F2 gives a 25mm diameter aperture (50/2 = 25). The smaller the F stop number, the larger the aperture diameter and the shorter the depth of field.   3.  Shutter Speed The amount of light captured will determine movement and in very low light conditions sufficient exposure. Each change in shutter speed stop, either doubles or halves the shutter speed. 4.  Sensitivity ISO sensitivity setting will compensate for the amount of light allowing aperture and shutter speeds to be optimised for the correct exposure. Digital cameras allow for different ISO speeds. The lower the number the finer the quality of the image. However to get the required aperture and shutter speed for the image being taken may result in under or over exposure. Adjusting the ISO will bring the image back to the correct exposure and therefore give a successful outcome. Getting these four to work together will allow you to produce your picture. Steve Costin, Webmaster © Isle of Thanet Photographic Society