Histograms:
Once you know the basics of cameras and composition, you’d almost be ready to take photographs, almost. You may be able to take decent photos but without any knowledge of lighting and balance you wont get very far. One of the most useful tools for identifying and visualizing proper lighting is the histogram. The histogram is the beige graph seen in the photo above. The graph ranges left to right. The left represents darks and shadows while the right is highlights and bright spots. The middle, naturally, represents the mid tones that are neither bright nor dark. The more intense that tone is the higher the vertical spike is in the histogram. Each tone is read from 0 to 225 pixels. Zero being pitch black, the left side of the histogram, and 225 being the brightest of whites, on the right side. Use of histograms in the field will save you a lot of disappointment. The tiny LCD screen of your camera will not always capture all the details of a photo taken, but the histogram will. Looking at a histogram directly after taking a photo will save you from losing out on good photos from any opportunities you may have had.
https://digital-photography-school.com/how-to-read-and-use-histograms/
Exposure compensation:
One more import thing to know, that is closely corelated to histograms is exposure compensation. You don’t want your photo to be too dark nor too light. When you look at a histogram you want the graph to relatively even in the disbursement of lights darks and mid tones. The photo above is within the ideal exposure range. While this photo, as stated with the histogram was far to underexposed.
While this photo is far to overexposed.
As stated before you want your tones evenly disbursed, and to achieve that you must correct your exposure by adjusting either shutter speed, aperture , or ISO, possibly all three.
Before we send you off on your merry way there are a few more terms to keep in mind
White Balance:
Most sources of light burn at different energy levels. The more intense the energy source the more blue the light is, the more cool the source is the more orange it is. In between the hot and cold is the neutral white you want to aim for. Because of this cameras have a white balance feature whether you know it or not. Most times cameras are automatically set to auto and can adjust to the current lighting conditions. However you can manually adjust the settings to your liking. If the light source is cooler than your setting it will show up in orange tones. If your light source is warmer than your setting it will appear blue. As an example here we have a photo taken in a cooler light source (tungsten) than the white balance settings (daylight)
https://www.digitalcameraworld.com/tutorials/cheat-sheet-white-balance-settings
Bracketing:
Bracketing is the practice of capturing a set of photos each one with slightly different camera settings. That way you end up with the same scene with a couple differences in each one. Like these two photos below.
Underexposed:
Underexposed photos are photos are photos that end up too dark because too little light was recorded. Now this isn’t always a bad thing as there are certain circumstances where underexposure leads to fantastic shots such as silhouettes. In the end the choice of whether to underexpose is up to the individuals desired effect.
Correct Exposure:
Having a correct exposure is the most commonly desired exposure type in photography. In correct exposure the image is neither too dark or too light and consists of the right amount of shadows highlights and mid tones. The mean of the histogram of the photo below sits at 121.11, which is just a few pixels shy of being the perfect average between dark and light.
Overexposed:
Overexposure is the exact opposite of underexposure where too much light is worked. Unlike underexposure, though, overexposure is almost never desirable. When a subject is over exposed the details are lost in the highlights and a bright spot will appear on your image, which can get very distracting. The photo below is slightly overexposed with the histogram mean sitting at 161.21 about 36 pixels above the perfect average. Fortunately this image is not ruined to the point of irreparability and most likely could be fixed in post production.
Finally with the help of the histogram I have provided a 9 image collage ranging from excessively dark to excessively light, to help better visualize what the histogram is telling you.
