The exposure in photography is one of the most important elements. Well, if you click everything in the auto mode, exposure will be adjusted automatically. But if you want to photograph, then you need to work with manual mode of the camera.
The of exposure (digital photography)
Exposure – the unit of measurement for the total amount of light reached the image sensor during each shot. The exposure is controlled with the Shutter speed, Aperture, and ISO. All three are together called exposure triangle.
The exposure triangle
Exposure consists of the three components: Aperture, Shutter Speed, and ISO. Each represents the equal side of the exposure triangle. To use this idea, just imagine the perfect triangle with equal sides. It is natural that to change the length of one side, you will need to change the lengths of other two sides too. All the elements in a triangle are related to each other, and of course, they are also related to the light condition you are shooting in.
Let’s consider a few examples with natural light
Let’s say, you like to photograph the portrait on a bright day. Additionally, you plan to focus on the eyes and blurred background. The background is also far away from the model. You may like to use “big aperture” (F/2 or F/4.5 depends on your lens) on a bright day, you may use ISO 100 to achieve a less noisy image. With this condition, your shutter speed will be very high, depending on the amount of light; it could be above 1/1000 or even more. Once you set up the Aperture and the ISO, you may change your shutter speed and check the result via the light meter in camera. When the indicator is in the center your settings are done. Try to remember them. In photography, a camera is just a tool to get amazing pictures, so it’s ideal if these settings come into your mind automatically- without disturbing the creative process.
Alternatively, you may like to photograph a friend with a lovely cityscape behind. But you would love to see details of the wonderful architecture behind. In such a situation, you will need to use a smaller aperture – F/7 or smaller (depends on your lens). As your aperture is now smaller, you need to adjust the other components. You may like to increase the ISO by about 200 or more, and then adjust the shutter speed the same way as you did in the previous example.
Both of the examples are relevant if you use manual mode. In other modes such as Shutter Speed priority or Aperture priority, the numbers will be decided automatically by a camera. If you use one of the automatic modes, everything may be decided by the camera. But please notice that human judgment leads to more creative and interesting photographs.
How to achieve the right exposure
The “Correct exposure” means you have enough details in a final image. The “Overexposed image” means the details in the light area were lost. The “Underexposed image” means the details in the dark areas were lost.
Most of the cameras have some sort of light meter. During the professional photo shoot, the photographers use the more sensitive external light meter. But for everyday shooting, the inbuilt light meter is good enough. The light meter indicates the exposure condition under natural light. But if you work with impulsive and unpredictable lights then you need external light meter such as Sekonic. The external equipment is quite expensive, so there is another way. You have to practice with your lights a lot and remember the numbers on your strobes or speed lights with relation to each camera setting. It sounds close to impossible, but after few months of practice, it will start working and your numbers will be close to the right measurements.
Keep the size of the Triangle equal. Remember the settings. Plan the shot. If you need more specific information, please check the articles from Photography 101 series.