Photography - Getting Properly Exposed Photographs - How to take correctly exposed pictures - Finding Proper Exposure
Are your Photos too Dark or Light?
If your photographs are coming out too dark or too light it is because your camera is not properly exposing the image. This makes the image either Overexposed or Under Exposed.
Underexposed images have received too much light and become darker.
Overexposed images have received too much light and become washed out.
If your images were under exposed you may be able to salvage the images through post processing. However, overexposed images usually are not as recoverable, as the more an image is overexposed the more detail is lost.
Getting a properly exposed photograph requires properly balancing your cameras aperture and shutter speed.
Correct Aperture + Correct Shutter Speed = Proper Exposure
When you go outside on a bright sunny day your eyes need to adjust to the light, the iris of your eyes will constrict and your pupil will become very small. When you are in a dark dimly lit room, your iris will relax and your pupil gets larger.
A camera's lens works a lot like your eye. Inside your lens has a set of blades which act as the iris. These blades open and close to control the size of the opening that light travels through, which is called the aperture.
The camera lens aperture is measured in f-stops which include f-1, f-1.4, f-2, f-2.8, f-4, f-5.6, f-8, f-11, f-16, f-22, f-32. The larger the f stop, the smaller the aperture opening and thus the less light it allows into the camera. The f-stop number is calculated by taking the focal length and dividing it by the diameter of the aperture opening.
The other way that your camera manages the amount of light is by the time that the shutter remains open, which is called the shutter speed.
The shutter speed of a camera is typically measured in fractions of seconds, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000. Likewise the shutter speed may also be notated as 1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000; with 1 being equal to 1 second and 1000 being equal to 1/1000 of a second.
Balancing Aperture and Shutter Speed
In order to get a properly exposed photograph we need to get the correct balance of Aperture and Shutter Speed.
The Exposure Value Table below can assist you in finding the correct Aperture and Shutter Speed settings based on the amount of available light. As you can see there can be several correct combination of Aperture and Shutter Speed for a single exposure value.
Exposure Value Table
General Exposure Values
EV 15 - direct sunlight.EV 12 - open shade on a sunny day.EV 7 - typical indoor lighting in offices, etc.
Your camera probably has an internal light meter which can automatically calculate the correct aperture and shutter speed. Your camera may have several settings or modes, which will regulate the aperture and shutter speed differently.
Automatic Mode - In Automatic Mode your camera will determine both the Aperture and Shutter Speed.
Aperture Priority Mode - In Aperture Priority Mode you set the Aperture that you would like and your camera and will calculate the correctly shutter speed for each shot. Using the Aperture Priority Mode you can open up your aperture wide to get a shallow depth of field.
Shutter Speed Priority Mode - In Shutter Speed Priority Mode you set the shutter speed and your camera will calculate the correct aperture for each shot. Using Shutter Speed Priority you can set a fast shutter speed to capture action shots.