Photography Exposure Settings FAQ

Shutter-speed refers to how long the shutter will remain open when the shutter button is pressed. Most cameras have shutter-speed settings that range from 30 seconds (very slow) to 1/4000th of a second (very fast). Slower speeds allow for more light to be let in, but can also show motion and cause the subject or the entire photo to be blurry. For example, when shooting hand-held, most photographers would shoot no slower than 1/60th of a second, in order to avoid any blurriness due to handshaking while holding the camera. Faster shutter-speeds let in less light, but can freeze the motion of fast moving subjects. For example, to freeze the motion of a running person you would want to shoot at 1/400th of a second or faster to freeze the action, slower than that and the person would be blurry in the photo.

Aperture is the opening inside the lens that allows light into the camera. It is the camera lens, not the camera, that dictates the aperture range you have available. Typical kit lenses have a range of F-3.5 (large) to F-32 (small). Lenses with larger apertures like F-2.8, F-2, F1.8, F1.4, and F-1.2 increase in price as the aperture gets bigger, the difference between an F-2 lens and an F-1.2 can be thousands of dollars. Larger apertures let more light in while reducing the depth of field. Though there is only ever one focal plane, one distance for the lens, that is truly in perfect focus, depth of field refers to how quickly the focus falls off, or how much of the photo will look as if it is in focus. For example, when you see a photo of the person in front of a display of lights, and the lights are just soft round blobs of light, a often desired effect called bokeh, a large aperture is being used to create a shallow depth of field. Conversely, smaller apertures let in less light, but have a larger depth of field. For example, landscape photographers often shoot at F-8 or higher, so most everything in the frame looks in focus.

In the digital era all the same terms and speeds have been carried over, but it works a slightly different way. A digital camera has a sensor that takes a baseline of power to work with a base ISO, which in most cameras is ISO 100. ISO 100 would produce the cleanest images that the camera can create. Increasing the ISO doesn’t make the sensor more sensitive, but instead amplifies the signal the sensor is capturing, similar to increasing the volume of a radio and amplifying the sound. And, similar to a radio, if you amplify the signal too much you start to add in distortion or noise. Higher ISOs can add a lot of digital noise to a photo. This is typically seen as red, green, blue, and/or purple dots in the dark areas of a photo, and less detail or clumpiness in the colors, and red, yellow, and/or white dots in the bright areas. But, a grainy or noisy photo is better than no photo at all, think back of how many famous photos, especially sports photos, are very grainy or noisy.