Finding the right balance between aperture, shutter speed and ISO is key to getting the perfect shot. When these three elements are combined, they represent the exposure value (EV) for that particular setting. A change in any one of these elements will affect the look of the photo.
When we talk about exposure, we simply mean the brightness or darkness of a photo. Often times you will hear someone say a photo is overexposed or underexposed; meaning the photo is either too bright or too dark. Either of these exposures can ruin a photo. Overexposure is when the information in the highlights is effectively unreadable. Underexposure is pretty much the same concept, except there is no image information contained within the shadows. This missing information cannot be retrieved through post-processing either. In digital photography, once that image information is gone, there’s no way to retrieve it. Only images that are slightly over or underexposed can be fixed through post process editing.
As we discussed in the previous posts, if you increase the f-stop, you reduce the amount of light hitting the sensor, but also increase the DOF (depth of field) of the image. Reducing the shutter speed affects how motion is captured, which can cause the background or subject to become blurry. However, reducing shutter speed also increases the amount of light hitting the image sensor, so everything is brighter. Increasing the ISO allows for shooting in lower light situations, but you increase the amount of digital noise in the photo.
For example, if your subject is moving and you want to freeze the motion, you will need a higher ISO setting to compensate for the high shutter speed and ensure your image gets enough light. In addition, if your image doesn’t require a large depth-of-field, you can use a lower f-stop, allowing more light into the lens and use a lower ISO. Using a tripod also changes things a bit. If you’re using a tripod to stabilize your camera you can usually get away with a slower shutter speed, which then allows you to use a lower ISO.
You can now customize your photos by using the aperture, shutter speed and ISO settings to create the perfect exposure for your photos. Happy shooting!
Tags: PHOTOGRAPHY 101