Digital Photography and Imaging

Week 1

What is shutter speed?

The basic rule of a Photographer to be learnt.

Shutter speed is ‘the amount of time that the shutter is open’.

In film photography it was the length of time that the film was exposed to the scene you’re photographing and similarly in digital photography shutter speed is the length of time that your image sensor ‘sees’ the scene you’re attempting to capture. Shutter speed is measured in seconds – or in most cases fractions of seconds. The bigger the denominator the faster the speed (ie 1/1000 is much faster than 1/30).

In most cases, usual usage shutter speeds are 1/60th of a second or faster. This is because anything slower than this is very difficult to use without getting camera shake. Camera shake is when the camera is moving while the shutter is open and results in blur in the photos.

While using a slow shutter speed (anything slower than 1/60) tripod is needed or some type of image stabilization (more and more cameras are coming with this built in).

Shutter speeds available on camera will usually double (approximately) with each setting. As a result, it usually have the options for the following shutter speeds – 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc. This ‘doubling’ is handy to keep in mind as aperture settings also double the amount of light that is let in – as a result increasing shutter speed by one stop and decreasing aperture by one stop should give the similar exposure levels.

Some cameras also give the option for very slow shutter speeds that are not fractions of seconds but are measured in seconds (for example 1 second, 10 seconds, 30 seconds etc). These are used in very low light situations, in going on special effects and/or when trying to capture a lot of movement in a shot. Some cameras also gives the option to shoot in ‘B’ (or ‘Bulb’) mode. Bulb mode lets you keep the shutter open for as long as you hold it down.

When considering what shutter speed to use in an image you should always ask yourself whether anything in your scene is moving and how you’d like to capture that movement. If there is movement in your scene you have the choice of either freezing the movement (so it looks still) or letting the moving object intentionally blur (giving it a sense of movement).

For the actual speeds for the image, the photographer should choose, and vary depending upon the speed of the subject in the shot and how much amount of blur wanted in it.( Darren R, 2014).

Introduction to shutter speed - dPS (2006) Available at: http://digital-photography-school.com/shutter-speed/ (Accessed: 20 July 2016).

What is aperture?

The aperture is a small set of blades in the lens that controls how much light will enter the camera.  The blades create an octagonal shape that can be widened (photographers call it shooting “wide open”), or closed down to a small hole.  Obviously, if it was shot with the aperture wide open, then more light is allowed into the camera than if the aperture is closed down to only allow a tiny hole of light to enter the camera.

So suppose a picture taken that is too bright.  How can it be fixed?  Simply choose a smaller aperture.  Aperture sizes are measured by f-stops.  A high f-stop like f-22 means that the aperture hole is quite small, and a low f-stop like f/3.5 means that the aperture is wide open. The size of the aperture controls more than the brightness or darkness of the picture, though.

The aperture also controls the depth-of-field.  Depth-of-field is how much of the picture is sharp, and how much is blurry.  If you want to take a picture of a person and have the background be blurry, it is the shallow depth of field.  If taking a picture of a sweeping mountain vista, a small aperture size (high f-stop number) so that the entire scene is in sharp focus.

(No Date) Available at: http://improvephotography.com/photography-basics/aperture-shutter-speed-and-iso/ (Accessed: 30 August 2016).