Understanding Exposure: Shutter speed, Aperture, ISO

Understanding Exposure

What is Exposure? to simply put it, it is the amount of light that enters the sensor in your camera. if your shot is exposed too long then it is overexposed or your photo will be too bright. If your shot is exposed too short the photo will appear too dark also. At least all if not most digital slr’s today have built in light meters which measure the light and set the exposure automatically (notice that ruler-like thing with a pointer on your view finder? that tells you the exposure reading that your camera sees in the frame).

Some photographers depend on a light meter which is not bad. but if you already know how to calculate and control your exposures you can get some creative and well exposed photo.

Photo by: Gilbert Caballero

The picture above was shot at slow shutter speeds and small apertures to blur the water movement and create a really nice and soft action. You can achieve this photo by using a tripod

There are two primary controls of your camera that adjusts the exposure, Shutter speed and Aperture. Shutter speed controls the amount of time the sensor is exposed to light, it is commonly showed as fractions of a second. Aperture on the otherhand, controls the lens opening that the light gets into the sensor), it is commonly showed as f stops, i.e. f2.8, f4, f5.6, note that the bigger the lens opening the smaller the f number, the smaller the lens opening the higher the f number.

There are a lot of ways in creating wonderful shots when you know how to control shutter speed and the aperture. Shutter speed may freeze or blur action, while aperture also controls the Depth of Field which is in focus in the picture and the background is out of focus.

One more thing to consider in exposure is called the ISO. Most digital SLR’s today have the ability to control the sensitivity of the sensor to light. THe higher the ISO speed the greater the camera collects light but with a downside which is you’ll get more noise to your photo.

For example if your trying to take pictures in low light without a tripod, you might want to increase your ISO speed in order to get a clearly focused picture.

Hope this article helps for those starting out.

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Related posts:

1. How to get sharp photos
2. When to use a tripod?
3. How to read the Histogram
4. How to create HDR images
5. Want to start into photography?