Photography terms: ISO Value

ISO value was firstly used in film cameras. It defined the sensitivity of a film in different units such as ASA, DIN and other. For example there were different ISO values such as 25 ASA, 50 ASA, 100, 200, 400, 800, 1600, 3200 ASA and other, so that was the sensitivity of a film where the lower number meant lower sensitivity. Now when buying films, you can usually find them with 100 or 200 ASA, which is written on a film so you can see it. If you have some films beside you, check for yourself! Films sensitivity is being different by the different size of dots from which the film is being formed, in other words, different sizes of dots or cells that accept light and form a picture. Smaller means smaller dots and less sensitivity, so the bigger number means bigger dots. By the way, films with bigger light sensitivity need less light to form a picture and inversely. So it is logical to always use the more sensitive film, but there is one problem - when you take a photo off the film and put it on a paper, the dots could be seen and they are not so pleasant to be seen. So the most common ISO values, as I said are between 100 and 400 ASA. In era of digital photography, ISO value is still being used to describe the sensitivity used for taking a picture. Same problem as with films is present and that is the size of dots in bigger sensitivities, but that is now almost adorned by the bigger resolutions and newer and more professional cameras. So now with ISO value of 6400 ASA, you can surely make a good picture at night with at least light you can have on normal exposure. On most of compact digital cameras ISO value can’t be changed but with any better digital camera you can change it by yourself or put it on automatic mode. My advice is to use the less ISO value as you can so you can get better quality of your photos.