Considerations When Buying a New Digital Camera


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Shutter Speed

Shutter speed will vary depending on the camera you plan to buy. Shutter speed refers to the amount of time your camera sensor is open 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 will end up with a completely white image. This is because your camera is exposed to light coming into its sensor for a full 30 seconds causing it to overexpose and therefor resulting in a completely white and useless image.

But let’s keep the “very sunny day” setting. Let’s say that you have your ISO settings set to 100 (the lowest for most DSLRs) and an aperture value of f/22 (we will talk about aperture in a bit). Let’s also say that you are using the fastest shutter speed your camera allows; we will give it 1/4000 of a second. Shooting with ISO 100 with an aperture value of f/22 and a shutter speed of 1/4000 still gives you an overexposed image in our “very sunny day” scenario. There are a number of ways to fix this, but I will just go over one solution to make it simple. If you have a camera with a faster shutter speed, such as 1/6000 or 1/8000, the images that we took in this scenario would not be overexposed as they are because the shutter is so fast that just a small amount of light is able to reach the camera sensor.Under and Over Exposure

  • 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 to 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 also affects how much light comes into the camera, so if you increase your ISO from 100 to 200, you are doubling your sensor’s sensitivity to light, meaning 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 seconds. In this example, if you change your ISO setting to 200 but leave your shutter speed at 1/125, you will over expose your image. If you leave your ISO setting at 100 but change your shutter speed to 1/250, you will underexpose your image. It is important to know that if you change one thing, you must also change another to compensate for that change.


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