All about Exposure
The histogram is a graph tool that helps photographers determine the exposure of their pictures. It represents all of the pixels in the image and wether they are blacks, midtowns (greys) or whites. The height of the peaks determine how many pixels there are with that tone. If your picture is correctly exposed, the graph will reach from edge to edge, showing that there is good contrast within the picture. In a perfect world, the histogram would be a bell shape showing that all the tones are evenly distributed. Some pictures can be lighter or darker though and still have a correct exposure. This would just make the majority of the pixels go to one side, but still reach both edges. If an image is incorrectly exposed, the pixels will not reach both edges. It could all be in the middle, not reaching either side, or it could have the majority of the pixels reaching one side and edge, but not the other. This can be fixed in editing, or even before the picture is taken. You can use the exposure compensation button on your camera to correctly expose your image before you take it. Exposure compensation is when the photographer overrides the cameras light meter to darken or brighten images before you picture is taken. Sometimes the light meter can detect the light incorrectly, so the exposure compensation is a great way to get it right for the lighting situation.
White Balance
This is a setting in your camera that can remove unwanted color cast in photos, so that whites in real life appear white in the photo. It takes into account the color temperature of the lighting in the picture and adjusts it so that the colors appear correct.
https://www.cambridgeincolour.com/tutorials/white-balance.htm
Histogram
A histogram is a graph that is used to measure the tones in photographs. It represents all of the pixels in an image and shows if they are whites, midtones or greys, or blacks. The height of the graph depends on how many pixels have that tone. The higher the peak, the more pixels.
https://digital-photography-school.com/how-to-read-and-use-histograms/
This photo has a pretty balance histogram.
Bracketing
Bracketing is when you take the same photo more than once but changing the settings each time for a different exposure. This can be a good way to just get different lighting in photographs, or it can help get the perfect exposure by combining all of the pictures so that each part of the picture is correctly exposed.
https://digital-photography-school.com/bracketing-what-is-it-and-what-to-do-with-the-images/
Exposure Compensation
Exposure compensation is when the photographer overrides the cameras light meter to darken or brighten images before you picture is taken. Sometimes the light meter can detect the light incorrectly, so the exposure compensation is a great way to override the default settings to get correct exposure for the lighting situation.
https://photographylife.com/what-is-exposure-compensation
Underexposed
An underexposed image is an image where there is not enough light in it. This can make the photo dark and dull, and often unable to be seen clearly. It also can be uninteresting to look at since it can lack contrast.
https://www.thesprucecrafts.com/underexposure-2688494
Correctly Exposed
An image that is correctly exposed is an image that isn’t too light or too dark. It will have a good amount of blacks and whites, shadows and highlights, and a lot inbetween. These photos will have good a good contrast of colors.
https://www.thesprucecrafts.com/underexposure-2688494
Overexposed
An image that is overexposed is the exact opposite of underexposed. There is too much light in the image and not enough darks. The photograph can become “blown out” and lack detail. Just like an underexposed image, an overexposed image will lack contrast.
A lot of the time, the histogram doesn’t end up perfectly edge to edge without editing it. This took me awhile to figure out. I was struggling to get the perfect histogram for awhile, and I was unable to do so just with the camera.
Photoshop Research
In terms of the whites and the blacks in a photo, it was pretty easy to determine what the edges of the histogram would look like while going through images that I have taken for this class. For the pixels that are in the middle of the histogram, it was kind of overwhelming to try to figure out what shape they would be in or how much in one spot of the histogram. Once I started looking at more images and started to identify which parts of the histogram corresponds to which part of the image, it became more clear to me. I also turned some images into black and white, so that it was easier for my brain to process the different kind of greys in it. This helped a lot and made it easier for me to figure out the basic shape of the histogram while the picture was in color.
Real Life/Application
To be able to tell if a photo is correctly exposed the histogram should reach edge to edge for the blacks and whites. This means that there is good contrast in the picture because there are bright areas as well as dark areas. Going through my photos, I had a lot that were underexposed. This makes the histogram have the majority of the pixels to the left of the chart, making a gap between them and the right (white) edge. This means that the photo is probably pretty dark and not correctly exposed. The same goes for the opposite on the histogram. If the majority of the pixels are on the right side, making a gap on the left (black) edge, this means the picture is overexposed and does no have good contrast. It was interesting to see that many of my pictures were underexposed, even on some that I thought were good. I will be much more considerate in the future now that I tend to go under.
