Now that you have a basic understanding of each of the three elements of the exposure triangle, that next thing to figure out is how to make sense of their relationships and how you can make them work for you and take good pictures.
A safe bet is to use a device called a light meter. However, I will assume that you don’t have one. I don’t. I also know only a few people who own or even use one on a regular basis. So, we’ll look at more accessible options.
Your camera can determine the proper settings for you with it’s own metering. A camera’s on-board computer packs programming which determines a safe exposure based on what your focusing on and the amount of available light. For reasons I no longer have any intention of covering in this course, it doesn’t always yield the result that you want. But they are serviceable, and can also act as a reference point for you to tweak your camera’s setting to your liking.
In case you would rather forego with the simpler and more straightforward approach above, you can choose to go old school. Before autofocusing came about, photographers had to figure exposure settings on their own. There was hardly any choice, like what we have now. On the other hand, people seemed to do fine back in the day.
Credit: Sakaris Ingolfsson
http://www.flickr.com/photos/sakariasingolfsson/
There are exposure charts that you can use as guides. You can also find an interactive Photography Exposure Wheel like this one. If you need something more convenient, if you have a smart phone, photography-related mobile apps which include exposure calculators now abound, as well.
Since we can never assume that all camera sensors are made equal, I doubt you will always get exactly the results you want from these tools. However, like relying on your camera’s programming, you will also be provided with serviceable starting points.
That is a key phrase you must remember: starting point. You are in no way forced to stick with whatever values you get from these tools. You are still the one who has the final decision on your exposure settings based on your own objectives. Make it a good one!