One of the settings that you may notice on your camera is ISO. This is a relatively new control that is used on digital cameras. On old film cameras, the ISO would equate to the film speed. Do you remember how you would need to buy a higher speed film to take more detailed, richer images? You no longer have to deal with that film speed, but not you have very precise control over the ISO so that you can take the best pictures.
ISO has to do with the image sensor in your camera. When you take a picture, light is exposed to that sensor and a picture is created. While you will actually be able to control just how much light is allowed to hit that sensor, you can also control just how sensitive that sensor is as well. This sensitivity level is the ISO. Because you can set the ISO, you will have much more control over how your image turns out.
Most likely, your digital camera will allow you to set the ISO to automatic, and you may find that this works for you in most situations. However, as you become more familiar with your camera, you may want to start controlling you own ISO to create the pictures that you want. When you look at ISO settings, you will see that they are listed in a set of numbers.
If the numbers are high, then the sensor in your camera will be more sensitive and light will have a bigger effect on your pictures. That means that a low ISO will make the sensor less sensitive.
One thing to note is that a high ISO allows you to take detailed pictures without a tripod, but when you use extremely high ISOs, your images will lose quality. You will need to be careful before you set it too high. Let’s discuss those different ISO speeds so you can get a better understanding of them.
When you look at this setting in your camera, you will see that the speeds start out with 100. Some cameras only go up to 1600. More advanced SLR cameras will let you go much higher on the ISO number, but we will just talk about the 100-1600 range. The numbers are exactly in conjunction with each other. If you set your camera to an ISO of 200, then it will be exactly double in sensitivity from 100.
Important Note: Remember how I mentioned that a high ISO will have an effect on the image? If you set this number to 800 or higher, you will see that the image gets grainy. This grainy effect is referred to as digital noise. You will most likely notice the noise in dark areas of the image. That means, if you take a picture with a very high ISO, you will most likely not want to print that picture any larger than a 4×6 so that the noise will not be noticeable.
Real Life Example: Have you ever tried to take pictures of fireworks? Of course, you will be taking pictures at night. If you allow your camera to set its own ISO, then it will set it high. Then, all of the dark spots on your image will have that digital noise. There are a great deal of dark spots of course. If you take charge of the ISO and lower it, you can still get beautiful images of the fireworks without so much noise. In situations like these, you will have to take charge of the ISO because your camera will become confused by the situation.