Want to learn what aperture, shutter speed and iso mean? Well in order to get a "correct" exposure, they must all work together. Go grab your camera and maybe some popcorn while I explain.
Here we go.........
Aperture is the size of the opening in your lens when the picture is taken. (the f #) You measure the size of the opening in f stops.The bigger the opening, the more light that enters the camera. The smaller the opening the less light that enters the camera.
The larger the aperture (bigger hole), the smaller the f-stop number. Ex. f/2.8
The smaller the aperture (smaller hole), the larger the f-stop number. Ex. f/22
Are you confused yet? I know I was at the beginning.
Shutter speed is the amount of time the shutter is open, (1/# of a second). The shutter speed is the key in preventing your subject from being blurred in pictures.
iso is the measure of the camera's sensor sensitivity to light. The best thing to know about iso is that the lower the # the better, for example an
iso of 100 = less digital noise (but just make sure to have lots of surrounding light around you)
iso of 1600 = more digital noise
*If you're indoors and don't have enough light, then you will have to have a higher iso, but remember the more noise you will have in your image.
To best explain how they all come together, I will use a metaphor to help you understand.
Imagine a water faucet, if light were water, a sensor would be like an 8oz glass. "Correct" exposure would be filling the glass. Not enough water means the glass can't be full (under exposed), too much water means the glass will overflow (over exposed).
Now to fill the glass properly and achieve the "correct" exposure you have the options of changing the opening in the faucet (aperture) and leaving the glass under the faucet for a necessary amount of time (shutter speed).
If your faucet is wide open, then you need less time to fill the glass, which means if you have a large aperture, therefore you need a faster shutter speed.
If your faucet is turned down, so water comes to a trickle, you will need more time to fill the glass. It means you have a small aperture, therefore, you need a slower shutter speed.
Now the iso would be the size of the glass. Rather than an 8 oz glass, we could use a 4 oz glass, which would require less water for it to be full. Remember, the higher you go, the more "noise" you will have in your picture.
By looking at this metaphor, it's clear that if you change one part of the exposure triangle, you have to change one or two of the other parts in the exposure triangle in order to have the same "correct" exposure.
There are many examples to explain how the exposure triangle works. This is the best explanation I can use, because it is how it was explained to me, where I could easily understand it. I hope you have found this helpful. Remember each photographer has their own preference, so play around till you find yours.
