If aperture, shutter, and sensitivity are called the three guardians. Then metering, exposure compensation and exposure mode must be the three little guardians. There is an interrelationship between them, and they are almost intertwined. However, unlike metering, exposure compensation is not easily ignored by photographers. In other words, when many friends cannot play with the aperture and shutter, they always expect to obtain accurate exposure through compensation.
I like to use an analogy. In the era when old TVs 30 years ago needed to use a pot to obtain TV signals, the aperture, shutter, and sensitivity were equivalent to twisting the pot to roughly find the central station, provincial stations, and local stations (regardless of whether each station was clear or not). Exposure compensation is equivalent to a fine-tuning function. You can slowly adjust the TV station you like to watch until the snowflakes disappear, the program is clear, and the sound is pure.
In fact, for this reason, when SLRs first became popular, many new photographers always worked hard on compensation, believing that this was the key to getting the best exposure, color and image quality.
Five of the 9 must-learn basics for getting started with photography | Exposure compensation
Exposure compensation
Exposure compensation: It is a method of exposure control, generally around ±2-3EV. If the ambient light source is dark, you can increase the exposure value (such as adjusting to +1EV, +2EV) to highlight the clarity of the picture. Exposure compensation is a shooting technique that consciously changes the "appropriate" exposure parameters automatically calculated by the camera to make the photo brighter or darker. Photographers can adjust the brightness and darkness of photos according to their own ideas to create unique visual effects. Generally speaking, the camera will change the aperture value or shutter speed to adjust the exposure value.
Exposure range: The exposure compensation range of almost all digital cameras is the same. It can be added or subtracted within plus or minus 2EV. However, the addition and subtraction are not continuous, but jump at intervals of 1/2EV or 1/3EV. Early old-fashioned digital cameras used 1/2EV as the interval, so there were 8 levels -2.0, -1.5, -1, -0.5 and +0.5, +1, +1.5, +2 (that is, adjusted with half-stop as the interval). The current mainstream digital cameras we see on the market are divided into more detailed levels, with intervals of 1/3EV (equivalent to dividing the first gear into three parts, three levels), so there are 12 levels of compensation values, including -2.0, -1.7, -1.3, -1.0, -0.7, -0.3 and +0.3, +0.7, +1.0, +1.3, +1.7, +2.0.
exposure compensation control diagram
automatic metering + exposure compensation = what the naked eye sees
Remember the above formula. We talked about the metering mode in the previous lesson. If the exposure parameters obtained by automatic metering are understood as the rough selection I mentioned earlier, then the exposure compensation is the fine adjustment when the exposure is not satisfactory, and finally obtains the shooting effect seen by our naked eyes. Exposure mode is a topic that will be discussed in the next lesson. It needs to be brought up in advance so that photographers who have always been ambiguous about when to use exposure compensation can understand whether their operations are meaningful. What’s interesting is that some cameras can still adjust the compensation value even in meaningless exposure modes. Therefore, the knowledge points that Uncle Tong talks about next are very crucial.
Exposure compensation control is as follows:
AUTO Invalid
P Acts on the aperture and shutter (outside the aperture capability range, all the workload is performed by the shutter)
A Acts on the shutter
S Acts on the aperture (does not work beyond the aperture capability range)
M Acts on the value, but the setting is invalid. If the flash is turned on, it acts on the flash.
and above, if you can’t understand it, just hold the camera and try it while operating it. Remember, exposure compensation is not about letting a third party work outside the aperture shutter. Instead, the compensation command is still assigned to the aperture shutter in the automatic state to work.
When in the AUTO fully automatic point-and-shoot mode, all controls are taken over by the camera, and even exposure compensation is not allowed to be operated by individuals.Some cameras have gray keys that cannot be moved, so just remember them in this mode.
In P mode, which is the program automatic exposure mode, if you adjust the compensation value, it will decompose the command (or task amount) to the aperture and shutter to work together, which is equivalent to two soldiers working for the compensation value at this time. If you increase the compensation beyond the maximum aperture, all the work is performed by slowing down the shutter.
is in A stop, because the aperture is set by you, then the compensation value will assign the command to the shutter.
is in S mode, because the shutter is set by you, then the compensation value will assign the command to the aperture. But if you increase the compensation beyond the maximum aperture, then the aperture will stop, which is equivalent to adjusting the compensation value blindly. At this time, there is no one to work.
In M mode, many cameras can still set the compensation value, but it is meaningless at this time, because the aperture and shutter are all set by you, and there is no third party to do it. If you are at a shooting scene and hear a teacher shouting: Use manual gear, and if the exposure is underexposed, increase the exposure compensation! Then you can look at this person with contempt, because he is a false teacher, knows nothing, and made a low-level mistake. However, if you turn on the top flash, or your off-camera hot shoe light is adjusted to TTL automatic mode, then the compensation value you increase at this time will be completed by the intensity of the light (this is what Uncle Tong accidentally discovered before, it is very interesting).
Schematic diagram of exposure compensation principle
Look at the picture above. There is no compensation value set on the left, 0. The aperture is F18 and the shutter is 1/250s. On the right, the compensation value is increased by 1 stop and a third of a stop, +1 (1/3). Because it is aperture priority, F18 remains unchanged. The shutter speed is slowed down to complete the task of exposure compensation delivery, from 1/250s to 1/100s, which is exactly 1 stop plus 1 stop.
White plus black minus:
About white plus black minus, its popularity goes far beyond "it is the head behind the lens that determines the quality of a photo." What is the principle?
When we shoot snow in winter, the camera's metering system prevents the white snow from being overexposed, so the snow that is automatically photographed will be black and lack the feeling of a first stop. Therefore, when automatically photographing white, we need to plus exposure compensation to obtain real white snow. As shown above.
When we shoot a pure black cat, the camera metering system prevents the black cat from turning into a dead black, so the black cat that is automatically photographed turns into a gray cat. At this time, minus exposure compensation is needed to obtain a truly black cat coat color. The fine adjustment compensation value of
is equivalent to manual fine-tuning to make the whitening process infinitely close to the unexposed edge (white snow), and the black reduction process to the black edge (black cat).
When you are completely familiar with adjusting the aperture and shutter, there is no need to play with exposure compensation. Finally, Uncle Tong will teach you a professional method of exposure - HDR photo shooting .
High Dynamic Range Imaging (English: High Dynamic Range Imaging, HDRI or HDR for short), in computer graphics and cinematography, is a set of technologies used to achieve a larger exposure dynamic range (ie, a greater difference between light and dark) than ordinary digital image technology. The purpose of high dynamic range imaging is to correctly represent the wide range of real-world brightness from direct sunlight to the darkest shadows.
When shooting landscape works, fix the camera on a tripod, adjust the exposure mode to P, and take five photos with different exposure compensations. The exposure compensations are -2.0, -1.0, 0, +1.0, +2.0. After getting five photo materials with different exposures, you can use PS to synthesize HDR. You must first open the PS software.
Step 1. Open five photos with different exposures, left-click "File", "Automatic", and "Merge to HDRPro".
Step 2: Click "Add Open File" again, click "OK", and the software will automatically process the image.
step 3. PS will display the original image and preview image. In the pop-up settings window, you can adjust and set different parameters. After the settings are completed, left-click "OK".
Petroleum Beauty | Uncle Tong’s work
Exposure compensation is very easy to understand. After mastering its principles, taking pictures will become more comfortable. Therefore, brothers, don’t aim too high, lay a solid foundation in photography, learn solidly, and you will have a promising future. Come on
!
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