- ISO - With respect to images, ISO refers to the sensitivity of camera to light. The higher is the ISO count, the lesser light is required to click a photograph which is properly exposed. Properly exposed means that the picture is neither too dark and nor too light. ISOs typically range between 100 and 1600. Sequential increase in ISO count is generally 100, 200, 400, 800, and 1600.
Generally, since there is enough of natural light in the daylight, an ISO of 100 or 200 is used outdoors. However, there is quite less light in the indoors (in the absence of a flash), so you take the ISO up to 400 or even more in order to bring more light into the picture.
- Shutter Speed - Shutter speed is how fast/slow a camera takes a picture. This depends upon how longer the shutter is open to allow the light to enter and reach the camera’s sensor.
- Aperture - Aperture setting is used to control the amount of light entering into the camera lens. Aperture is actually the diameter of the lens opening. The larger is the diameter (or aperture), the more light enters and reaches the image sensor.The value of aperture is given as “F-Stop” or “F-Number”, expressed as f2.8, f4, f5.6, f8, f11 etc.
Now that you have learnt about various modes in a DSLR camera, don't limit yourself to the "Auto" mode!