Monday, 20 August 2012

Introduction to Shutter Speed

Shutter speed or exposure time is the length of time the camera’s shutter is open. It is shutter speed that controls how long the camera’s sensor will be exposed to light. A faster shutter speed means shorter exposure time and slower shutter speed means longer exposure time. Shutter speed is among the three elements that determine the exposure the other two being ISO and Aperture. We will discuss the relationship between the three and their impact on exposure in a later article the Exposure Triangle.

Shutter Speed
Photo By Kirstinmckee

Shutter speed is measured in seconds or to be precise fraction of seconds like 1/30, 1/60, 1/125, 1/250 and so on. The bigger the denominator the faster the shutter speeds and vice versa. Shutter speed has a direct correlation of 1:1 with aperture in determining the exposure. For any given exposure combination, if the aperture increases by 1 stop e.g. f/4 – f/5.6 or f/8 - f/11 then shutter speed will also decrease proportionately, like in this case the effective shutter speed will be half that of the original value e.g. 1/1000 – 1/500 or 1/250 – 1/125. If the aperture is decreased by 1 stop then the shutter speed will be doubled to attain correct exposure.

What shutter speed do I need to use?

Shutter Speed
Photo By Expressmonorail

The choice of shutter speed for a picture is largely determined mostly by the following factors:
  •     Whether the subject is moving or stationary.
  •     If the subject is moving – the speed of movement of the subject.
  •     In what direction is the subject moving – is it moving towards or away from the camera or is it moving from side to side.
  •     At what focal length is the shot being taken
  •     Is the camera on a tripod or shooting hand held – if shooting hand held does it have image stabilization (IS)
  •     What is the intended effect in the final picture – do you want to freeze motion or do you want to capture it.

If you are shooting a stationary object with the camera on a tripod then what determines your shutter speed is the aperture setting you wish to use. Wider the aperture, faster the shutter speed and vice versa. It is when you start photographing moving objects with the camera hand held that you need to be careful about your shutter speeds.

Shutter Speed
Photo By Mugley

 General rule of thumb is to use a shutter speed with the denominator that is larger than the focal length of the lens for e.g. if you are shooting with a 100 mm lens use a shutter speed of 1/100 or faster to eliminate camera shake. Image stabilization if available will help you shoot sharp images hand held at shutter speeds much lower than what is said in this rule of thumb, how much slower is determined by the effectiveness of your camera’s IS system.

When photographing moving subjects, shutter speed to be used is determined by whether or not you wish to freeze motion or capture it in your shots. In both cases the speed at which the subject is moving is what determines the shutter speed for the shot. The faster the subject is moving the faster the shutter speed needed to freeze and vice versa

Now let us have a look at shutter speeds to be used at the most common photographic situations

Shutter speed                                                Typical Examples

Bulb (1 minute to several hours)                Astro-photography – shooting star trials - Camera on a tripod

Shutter Speed in astrophotography
Photo By V4idas

1 – 30 seconds

Motion blur effect – low light photography - Night photography - Camera on a tripod

Shutter Speed in night photography
Photo By Nzdave

2 - 1/2 second

Motion blur effect to photographs (other than panning shots) photographing stationary subjects in very low light - To add a silky look to flowing water – To enhance depth of field in landscape photography - Camera on a tripod

Shutter Speed waterfall photography
Photo By Dirgon

1/2 to 1/30 second

For panning subjects moving slower than 30 miles per hour 48 km/h) and for available-light photography. – camera  preferably on a tripod else hand-held with image stabilization.

Shutter Speed panning
Photo By Strandloper

1/50 - 1/100 second

Focal length up to medium zoom - Available light portraits – photography in dim light – panning shots – camera hand-held

Shutter Speed available light portrait
Photo By Melodramababs

1/250 - 1/500 second

Longer zoom – hand-held - Freeze motion of people – action /sports 1/250 s is the fastest speed useful for panning

Shutter Speed sports photography
Photo By Ryusha

1/1000 - 1/4000 second

sharp photographs of moderately fast subjects under normal lighting conditions – camera hand-held

Shutter Speed high speed photography
Photo By Matt Hintsa

Shutter speed is one camera setting that has the widest range of creative possibilities; we will discuss it in detail in a future article - Creative Use of Shutter Speed.

In the next article we will discuss about Photography - Tips For Beginners - Understanding Exposure – The Exposure Triangle

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