A new technique for beginners...Beginners tend to face problems why getting the right exposure. The shot has the perfect composition, perspective and everything, but unfortunately it's not perfectly exposed. Instead of getting frustrated with your camera and cursing, why not learn this technique called The Exposure Triangle? The concept is simple, tweak any one of them to compensate for the other. But first, let's go through what's in the exposure triangle...
The three components in the exposure triangle is:
- shutter speed
The ISO is the sensitivity of the sensor. The higher the ISO, the more sensitive the sensor will be. But, there are drawbacks from this. Noise, a term of the presence for colour pixels where there should be none, will start appearing. Now, DSLRs these days offer the NR feature(Noise Reduction) but do note that this will degrade your picture quality.
Moving on to the shutter speed. Like our eye, we have to blink. Quite similarly, the camera has to do the same to take a shot. Shutter speed means the shutter of which it opens and closes. The shutter speed itself is a very crucial tool depending on what your subject is. If you're after motion, you'll be needing a slower shutter speed like 1/2 second all the way to 10 seconds. If it's sports, then obviously you'll be needing a (very)fast shutter speed like 1/500 second to catch the action.
Lastly, aperture. Aperture is a term for the size of the lens' hole. The bigger the aperture, the more light enters. Other than the increase of light entering, you'll also get a shallower depth of field or more commonly used as DOF. I love bokeh shots(the isolation of the subject from the background as an effect from the depth of field) as it gives an interesting look to your shot. Getting faster lenses is perhaps the most effective way to compensate. However, do note that primes can come in quite costly especially at the far telephoto end.
From Digital Photography School
Digital Photography School gave a really good example of this technique: