How to get it in practice
What could be simpler?
Take a picture;
Take a look at the histogram;
If the exposure is in order-it’s in the hat;
If the histogram indicates underexposure or overexposure, use exposure correction to increase or decrease the exposure, then go back to step 1.
Repeat the sequence until you are satisfied.
To get the correct exposure when shooting with a digital camera, in most cases it is enough to follow a simple and universal rule: you should give as much exposure as possible without the appearance of clipping.
Exposure in digital photography is dialectical. On the one hand, the greater the exposure, the higher the image quality due to better transmission of halftones and lower noise levels. On the other hand, for a digital image, there is nothing worse than overexposing plot-relevant objects. If too dark shadows are still quite real to lighten, though at the cost of some deterioration in quality, then it is almost impossible to restore the knocked out lights.
You need to bring the histogram as close as possible to the right edge, but do not touch it. This approach is also called ETTR (Exposure To The Right). Ideally, you provide a good study of details in the shadows, but do not allow knocking out lights. However, the shooting conditions are rarely perfect, and there may be some difficulties when trying to achieve optimal exposure.
Very bright objects in the frame
Exposure strictly to light is not always the best solution. Sometimes, to avoid clipping, you may need to reduce the exposure so much that the entire image, except for individual bright spots, will sink into darkness. In fact, in such cases, it is quite possible to allow some overlap. The disk of the sun, reflections on water or metal surfaces do not need details. You can safely ignore such things and exhibit the scene as if they were not there.
Also, clipping is perfectly appropriate when shooting objects on a white background. In this case, it is important for you to correctly expose the object itself, and if the background is knocked out – so much the better, you do not have to lighten it later.
When shooting in ambient light, a beautiful glowing halo often appears around objects. Its brightness is usually much higher than the brightness of the dark side of the object facing you, and an attempt to expose the frame by light will result in a very strong overall underexposure. In this regard, the light contour is forgivable to rest on the right edge of the histogram. Its artistic expressiveness will not suffer much due to the lack of details. Even better, if you have the option to highlight the dark side with a flash or reflector.
If the contrast of the scene significantly exceeds the dynamic range of the sensor, then, trying to avoid overexposure in the lights, we are forced to leave the shadows completely black. This is usually not a problem. In many scenes the shadows, the details are not important, it is possible to donate. If this is not acceptable, wait for a better light, or try changing it yourself.
It happens that frames exposed to light look dark. If you’re shooting in RAW, don’t pay attention. With post-processing, you can raise the brightness to the level you want, while keeping the details in the lights. If you are shooting in JPEG, then I advise you to achieve the correct exposure of plot-significant objects on the spot, and if this leads to the loss of details in the lights, then, well, there they go.
The brightness range of some scenes does not exceed several exposure levels. Such, for example, are many landscapes in the fog. If you move the histogram to the right, these scenes may look too light. When shooting in RAW, this is normal. You will always have time to reduce the brightness to your liking, but you will get a better tonal separation in the shadows and a lower noise level than if you had originally shot with the “correct” exposure. If you’re shooting in JPEG, you don’t have a choice – just expose it right away, even if the histogram doesn’t reach the right edge.
High ISO values
ISO sensitivity is increased when a short shutter speed is desperately needed, and it is not possible to open the aperture even wider. In such cases, you can deliberately go for underexposure, ignoring the ETTR rule, provided that you are shooting in RAW. The fact is that a photo taken with underexposure and then clarified in a RAW Converter has about the same noise level as a photo taken with normal exposure with a proportionally increased ISO sensitivity. That is, underexposure followed by clarification (digital push process) is equivalent to increasing ISO. Both give the same gain in shutter speed, but the known underexposure insures the light from possible overexposure, which is important when you are shooting in a hurry and you have no time to look at the histogram of each frame.