"You Press the Button, We Do the Rest" was an advertising slogan coined by George Eastman, the founder of Kodak, in 1888. Eastman believed in making photography available to the world, and making it possible for anyone who had the desire to take great pictures.
Today’s digital cameras, including your cell phone, make that as true today as it was over 130 years ago, although today’s cameras are much smarter than then. A camera today is really a computer wrapped around a lens. It is a very specialized computer, designed to provide the best possible image it can, given the conditions it “sees”.
Between the time you start pushing the shutter button and the time it is fully depressed your camera has to make decisions on how far away or close your subject is, how much light it has available, and what to focus on.
A proper exposure has to balance three things. How much light to let in [Aperture], how long to let that light through the aperture [shutter speed] and how sensitive is the sensor to that light [ISO]. This is collectively known as the “exposure triangle”. Whenever a change in one of these values is made it impacts the value of the other two, so that the picture is properly exposed.
For the most part, leaving your camera on the automatic settings is going to get you a great picture. But remember, someone programmed that computer that is your camera. They programmed it to give you the best results in the majority of situations you are trying to capture.
What this means is that your camera is trying to make every picture average. You, have to be smarter than a computer!. Well, not really, smarter, but at least be in control of it. That’s why there are all those other settings available to you.
Only you are smart enough to evaluate a scene and figure out that average just ain’t gonna cut it. Time to step up and show that you are smarter than a computer.
Before you take a picture, stop for a second and look at what you want to capture. If it’s a bright sunny day and you are outside, leave the camera on automatic; that’s what it does best and that is what it was programmed to do. On the other hand, take a look at the scene in front of you and try to match it to the scene settings on your camera. Your pictures will improve dramatically.
For example: you want to take a picture of the kids playing in the water. You want to. In effect, stop the motion. This means you need a fast shatter speed to make that happen. The “sport” setting on your camera is programmed to set your camera so that the shutter is fast and the other settings [ISO and Aperture], are set accordingly to result in a great exposure.
Another example: You want to get a nice picture of your friend but there is a lot of “clutter” in the background. Use the “portrait” setting on your camera. This setting controls how much of the scene is in focus. This is known as “Depth of Field”, and is controlled by how big the opening [aperture] is. The bigger the opening, the shallower the depth of field and anything that is not in the focused area will look soft and blurry. This setting controls the aperture and lets the camera decide what the settings are for the other two [shutter and ISO].
Finally, if you are trying to get a well exposed picture and you are low-lit room, maybe like a restaurant, try using the night mode. This controls the ISO, or sensitivity, of the sensor, enabling you to get good images in low light situations.
There are a number of settings on your camera. Try them all out in different situations; see what works. You are smarter than your camera.