What exactly is Shutter Speed?
Simply put – shutter speed is ‘the length of time in which the shutter is open’.
In film photography it used to be the time the film was exposed to a scene you are shooting, and likewise in digital photography shutter speed is considered the period of time that the photo sensing unit ‘sees’ the scene you are trying to shoot.
I will make an attempt to break-down the subject of “Shutter Speed” into some bite-sized pieces that will assist camera owners attempting to get their mind around shutter speed:
Shutter speed is calculated in seconds – or even in many cases fractions of seconds. The larger the fraction the quicker the speed ( 1/1000 is significantly faster than 1/30).
Most of the time you will likely be utilizing shutter-speeds of 1/60 of a second or even faster. This is due to the fact that anything slower will be very hard to make use of without experiencing camera shake. This occurs when the camera moves and the shutter is open, which causes blur in the photos.
If you are utilizing a shutter speed that’s slow (anything slower than 1/60) it is important to either work with a tripod or any form of image stabilization (increasingly more cameras are having this built-in).
Shutter speeds accessible to you on the camera will approximately double with every setting. Thus you will often have the options when it comes to the following shutter-speeds – 1/500, 1/250, 1/125, 1/60, 1/30 and so on. This ‘doubling’ can be helpful to bear in mind since Aperture settings as well double the volume of light that’s allowed in – consequently, raising shutter speed by a single stop plus lowering Aperture by a single stop ought to provide you with comparable exposure values.
Some digital cameras also provide you with the choice for really slow shutter-speeds that aren’t fractions of seconds but rather gauged in seconds (such as 1 second, 10 seconds, 20 seconds etc). They’re utilized in really low light conditions, when you are pursuing special effects as well as if you are attempting to capture lots of motion in the shot. Many cameras as well provide you with the ability to take a shot in ‘B’ (or ‘Bulb’) mode. B mode helps you to maintain the shutter open provided you keep holding it down.
When thinking about which shutter speed would be best in a photo you need to consider if anything in the shot is moving and the way you would want to capture that motion. If you have movement in the scene there is the option of either to freeze the movement (so that it appears still) or to intentionally let the active object blur (granting it a sense of motion).
To freeze motion in a photo ( similar to the surfing image above ) you will want to select a shutter speed that is faster, also to let the movement blur, you will need to select a shutter speed that’s slower. The speeds you need to choose will be different, dependant on the speed of the subject matter in the shot and just how much you would like it blurred.
There are occasions when motion is great. For instance when you are taking an image of a waterfall and would like to show how quickly the water flows, or when you are capturing a shot of a racing car and would like to give it a sense of speed, or if you are taking a photo of a star scape and would like to show the way the stars move over a longer time period. In most of these cases selecting a lengthier shutter speed would be the best choice. Yet, in all these instances you should utilize a tripod or you risk ruining the shots due to camera movement ( which creates a different sort of blur when compared to motion blur ).
Shutter Speed and Focal Length – one more thing to take into account when selecting shutter speed happens to be the lens focal length you are using. The total amount of camera shake you’ve got is accentuated by longer focal lengths, and thus you will have to opt for a quicker shutter speed ( unless of course you’ve got photo stabilization in the lens or camera ). The ‘rule’ of thumb to make use of with focal length ( in non image stabilized situations ) would be to select a shutter speed with a denominator that’s bigger than the focal length of the lens. As an example for those who have a lens which is 50mm 1/60th it’s probably ok however, if you’ve got a 200mm lens you will likely wish to snap shoots at around 1/250.
Keep in mind that planning on Shutter Speed separate from the other components of the Exposure Triangle ( ISO and aperture ) isn’t recommended. When you modify shutter speed you will have to change one or both the other components to make up for it.
For instance should you speed up your shutter speed one stop ( such as from 1/125th to 1/250th ) you are basically allowing half the amount of light into the camera. To make up for this you will likely have to raise your aperture by one stop ( such as from f16 to f11 ). Another approach is to select an ISO rating that is faster ( you may want to shift from ISO 100 to ISO 400 as an example ).