All photographers, irrespective of their level of experience, know the term ISO as it is one of the essential requisites, which enables them to take effective photos in varied light conditions. As one of the three components of the exposure triangle, the ISO setting is defined as a value which represents the sensitivity of the digital camera’s image sensor. This value is expressed in form of a definite number and is inversely proportional to the amount of light meaning that the lesser the ISO value, the more is the light required and vice versa. If you take a look at the two photos below you will notice the effect that the different ISO settings have on the final outcome – the one on the left has been taken 100 ISO and the one on the right at 3200.
It is essential for a photographer to adjust the ISO value while taking a photograph in combination with the shutter speed as well as the aperture because it is this setting which determines the final outcome of the photograph. Therefore, whether it is a professional photographer trying his talents in a deep rain forest or an amateur practicing at a concert, unless the ISO setting is adjusted in accordance with the amount of light in the surroundings, one would only end up taking dark images.
While selecting an ISO setting, there are four parameters which need to be kept in mind by the photographer namely light, grain, tripod and the status of the subject. While reference to light is to inquire whether the subject is well lit, the reference to grain whether it is a finer grain, which is required along with its noisiness. Likewise, the status determines whether the subject is moving or stationary and the fourth factor pertains to the use of tripod by the photographer.
Many photographers tend to take pictures with their digital cameras set in the ‘Auto Mode’ since in this mode the camera determines its own ISO setting in accordance with the surrounding conditions. In case the individual wishes to select his own specific ISO, then it should be accompanied by a change in the aperture setting and shutter speed as well. The ISO value, which is the normally accepted norm for acquiring crisp shots with the least amount of noise and grain is 100, although it can be altered either way.
And 100 is considered to be the optimum ISO value because a value which is higher than this figure results in noisy images with more grain. Although people do not mind a bit of noise since it does not always disturb the picture, there are other demerits which are likely to occur like reduced sharpness and reduced contrast ratio. However, these are minor problems which could be overcome by opting for a more technologically advanced camera.
Certain situations that call for a higher ISO setting are indoor sports events which involve a fast moving subject in a limited light setting, concerts which also feature limited light, art galleries and churches and birthday parties. Similarly, situations which could be shot with a low ISO value are shooting a stream, taking pictures of a field on a sunny day and trying to take photographs indoors without the images being too bright.
An adept photographer is always quick to realize the importance of the ISO setting in a digital camera and hence dedicates his efforts towards getting in-depth understanding of the subject. Ultimately, mastery in this area could be acquired by practically experimenting with different ISO settings and judging their impact on the photograph.