Shutter speed varies depending on the camera. It refers to the amount of time the camera sensor is opened and exposed to light. If you are out on a very sunny day and take a picture with a 30 second exposure (which I hope you wouldn’t), you would end up with an overexposed image. This is because the camera is exposed to light coming into its sensor for a full 30 seconds causing it to overexpose.
On a sunny day, let’s say you have your ISO settings set to 400 and an aperture value of f/4.5 (we will talk about aperture in a bit). Let’s also say you are using a shutter speed of 1/500 of a second. Shooting with ISO 400 with an aperture value of f/4.5 and a shutter speed of 1/500 results in an overexposed image on this sunny day. There are a few ways of fixing this, but I will go over one solution to make it simple. Selecting a faster shutter speed can prevent overexposed images. Switching to a shutter speed of 1/1000 or 1/2000 could fix this problem. A faster shutter speed prevents more light from hitting the sensor, which should correctly expose the image in our sunny day scenario.
- In this example, the left image is under exposed. It is too dark and shows no details in any of the dark objects.
- The middle image is over exposed. This results in an image with no definition to the brighter areas.
- The image to the right has a correctly balanced exposure. You can now see all of the details in the darker and brighter objects.
Remember, ISO and aperture settings would also affect how much light goes into the camera. If you increase your ISO from 100 to 200, you are doubling your sensor’s sensitivity to light. Because of this, you must also double your shutter speed to compensate for that change. For instance, you initially shot a photo with an ISO setting of 100 and a shutter speed of 1/125 of a second. But since you increased your ISO setting to 200, you must also increase your shutter speed to 1/250 of a seconds to balance the exposure. In this example, if you change your ISO setting to 200 but leave your shutter speed at 1/125, you would over expose your image. If you leave your ISO setting at 100 but change your shutter speed to 1/250, you would underexpose your image. It is important to know if you change one thing, you must also change another to compensate for that change.