Hi welcome back it's Karen from the photography playground. To properly expose for any given scene you need a given amount of light. This amount of light is called the exposure value. The exposure triangle translates the exposure value into a combination of shutter speed aperture and ISO value. where it becomes interesting is how to achieve the exposure value. We distinguish two ways to work with the exposure value and the exposure triangle.
You can get the exposure value the same by decreasing one and increasing the order the same amount and you can enter overexpose, by increasing or decreasing one value. We call it exposure compensation. Now why would you want to do that? Because your smartphone camera measures all the different areas in the scene, the bright areas, the dark areas and everything in between it then calculate It's an average of all those areas and it comes up with an exposure value that might not fit you're seeing. For instance, if you have a dark scene was an important small bright area and the camera will think there's very little light because of the larger dark area. It will come up with an exposure value that will result in the overexposure of the bright area.
In a case like this, you need to underexpose when you underexposed, you let less light fall on the sensor then the exposure value indicate you achieve under exposure by giving less time and keeping the sensitivity the same, or you can make the sensor less sensitive was giving the same time of course you can also decrease both values. And if you have a bright scene with an important small dark area, the camera thinks there's a lot of light because of the larger bright area. It will come up with an exposure value that will result in the under exposure of the dark area. In a case like this, you To overexpose, when you overexposure let more light fall on the sensor then the exposure value indicate you achieve over exposure by giving more time and keeping the sensitivity the same. Or you can make the sensor more sensitive whilst giving the same time.
Of course, you can also increase both values. In the coming lectures, you learn to work with the camera app so you'll be able to set your camera as you wish. So you end there and in the meantime, happy photographing