Hello, in today's lesson you'll learn more about the histogram, both in your camera and in Lightroom. A clear understanding of how to interpret the histogram and apply adjustments accordingly is paramount for optimal image quality. The histogram, which lives at the top of the edit panel in Lightroom, is a graphic representation of all the tones and colors in the currently selected image. It provides information about exposures, tonal range, color balance, and distribution. The left-hand side of the histogram indicates the color and tone of the shadow areas, the middle, the color and tone of the mid-tones and the right side, the color and tone of the highlight. In an average scene, there is a predominance of middle tone, some shadows, and some highlights depending upon the overall contrast range of the image. Here is a typical mountain range histogram with a lot of mid-tone. There is also a good range from light to dark. In a properly exposed image of an average scene, we should see a broad distribution of tones and colors from shadows to highlight, without parts of the graph going off the chart from the left to right or top to bottom. For example, a very flat part of the graph in the shadows indicate loss detail in those areas of the image. Likewise, if the highlights were too high up in the graph adjusting the exposure slider in either direction shows what can happen. The small triangle at the upper left four shadow clipping and upper right for highlight clipping can be enabled by clicking on the triangles to enable these clipping the warnings. Clipping means some detail will not be visible on those areas and a color overlay shows the specific parts of the image affected. Blue for shadow clipping. Red for highlight clipping. Most of the time clipping is to be avoided. However, in the case of very bright light sources, or reflections of light sources in glass or metal there is no detail to retain. So when those areas show red it's not a concern. If it is an area of the image that should have some texture and detail in the highlight, then clipping is not desirable. The same is true to a lesser degree in the shadow areas. Textured shadow areas should be preserved, but some very dark shadow areas can go completely black in your image if there is no important detail there to preserve. While most images will have that average histogram, there's notable exceptions. For example, an image with a predominance of light tones, such as in a snow scene with light tone subjects like a snowman, the histogram would be shifted far to the right with very little to no shadow areas. Conversely, a very dark toned image, such as dark objects on the black leather background would shift the histogram far to the left. Both images would be considered to be properly exposed if the histogram appeared this way. While raw files in Lightroom are more forgiving of exposure errors than JPEG images, there are of course limits to that. Severely under-exposed images adjusted in Lightroom to brighten them to the maximum will show significant noise, which is a very grainy appearance sometimes contaminated with random colored pixels. Not a good look. At the other end of the exposure spectrum while highlight detail is definitely greater than provided by JPEGs, if the image is severely overexposed, Lightroom cannot recover detail that the camera cannot record. The camera has a histogram too and that is what you should use to evaluate your exposure on the LCD screen. Do not base your exposure assessment solely on the preview image. The brightness of that image can be adjusted very dark, or very bright in the camera's settings. It is only there to show you the capture, not tell you anything about exposure. You should adjust your exposure if the parts of the graph are off the chart horizontally or vertically. Of course, if the scene has a predominance of darks the histogram will be shifted left. If a predominance of lights, more to the right, but you should not see clipped areas of important detail in either case. The better your exposure, the better image quality you will preserve. Remember the camera doesn't understand anything about how you want to depict your subject. It just indicates an average exposure for an average scene with a full range of shadows, mid-tones and highlight. That average is a middle gray. So that's what your standard camera meter set up thinks the whole world is, middle gray. If you're seen as much lighter, or much darker, you should compensate by giving more exposure for a light scene, less for a dark scene. Use the exposure compensation dial, or manual mode to override the meters indicated exposure. You can always shoot a range of exposures called a bracket to cover the scene if the subject matter permits. Remember the human eye can perceive much more of a range of tone and color than a camera can. You should learn to see the world the way your camera does with practice and compensate as needed. We have seen in this lesson that the histogram is an essential tool for achieving top image quality. both in the camera and in Lightroom, You've learned a bit more about how to interpret the graph and how you could compensate for the camera's shortcomings by understanding what the graph is telling you about the scene. In the next lesson we'll dive into greater detail on the use of profiles and presets for creative image interpretation. Let's take a look.
