An old style shutter control dial - Ashley Beolens
I've said this before but I think it is a valid point to make (even repeatedly). Photography is about capturing light. It has been likened to painting with light (however this can also relate to another technique of photography so I'm not going to use that).
Photography is all about exposing your sensor (or film) to the right amount of light to correctly expose the scene in front of you, this is done with the cameras shutter (other factors are used to determine the shutter speed; but in all cases, no matter what your other settings, it is the amount of time your shutter is open that determines how well exposed the photograph will be).
On fully automatic modes (or partial modes in cases like aperture priority) the shutter speed will be determined by your camera, but most cameras will allow you to control the shutter speed yourself, either through manual or shutter priority modes.
Shutter speeds are generally measured in parts of a second - 1/500 equates to your shutter being open (to allow light in) for one (1) five hundredth (500ths) of a second (you obviously can have your shutter open for much longer in seconds or with certain settings for as long as the shutter button is pressed), the blow chart shows the standard shutter speed settings:
A fast shutter speed was needed to freeze the owl in motion İAshley Beolens http://beolens.redbubble.com/
Bulb - as long as you hold down the shutter release button.
In many cameras nowadays there are 1/3 (one third) incremental steps, in-between those listed above (your camera manual should inform you of these). There are also steps above (1/16000 etc) and below (2sec, 3secs and the relative incremental steps) the settings of the above chart.
Full manual mode as you would imagine gives you full control over shutter and aperture and is the setting that allows for the most independent alterations of a photograph. Shutter priority mode means you select the shutter speed you want to achieve and the camera will alter ISO and aperture to make this happen (as much as possible).
What determines shutter speed
As you would imagine, your shutter speed is determined by a number of factors, firstly it is the light. It will take a certain amount of light coming through your lens onto your sensor in order to correctly expose your photograph, and if you work on a base level that is all that dictates shutter speed (the same level of light produced will always require the same amount of light hitting the sensor to expose the photograph correctly - this is why controlled studio light is so effective). However as explained in understanding exposure there are other ways to get that light rather than one set timing for opening the shutter. Look at Exposure value, ISO sensitivity in understanding exposure or adding/subtracting light or focal length links, both found later in this tutorial, as ways to alter shutter speeds.
Focal length and shutter speed
It is worth thinking about the lens you are using when talking about shutter speeds, this is because there is a rule of thumb that says for hand holding a lens comfortably the shutter speed should be equivalent or above (faster) than the length of the lens.
An example of how a slow shutter speed has completely altered this image, it shows movement, both of the back ground and the subject İAshley Beolens
In other words a 400mm lens should be used (hand held) with a minimum shutter speed of 1/400 (the higher above the better), a 200mm lens at minimum shutter of 1/200 and so on. This rule is kind of altered with modern image stabilization advances (these can usually give an extra couple of stops.
Other shutter controlling elements
So from other tutorials we have seen how aperture or ISO can affect shutter speeds, and we have seen above how lens focal length can help determine the shutter speed but what else will change the shutter value?
To answer that question we must look at external elements that we can introduce that will alter the light coming through the lens (as discussed it is light levels that affect shutter speeds). One option we have (especially in close quarters) is to add light through flashes or static lights (be they studio lights or strobes), with this we will be increasing the light levels and therefore speeding up the shutter times (limitations apply with flash durations etc.). Alternatively we can redirect some of the light already available through the employment of reflectors (bouncing light back to where we want it, think of a mirror and how it brightens a room when placed opposite a window, reflectors work in the same way).
If we want to reduce the light levels we can add elements to the lens in the form of neutral density (ND) filters, these are dark pieces of glass/plastic that while reducing light allow the same clarity of light (hence the neutral bit) If you see images of milky water it is usually using this technique. We can also use reflectors but instead of with light coloured material we use blacks, these absorb light and prevent it being reflected back.
Shutter control use
So now you can understand what your shutter does and a little about how to control its speed, but why would you want to? surely all you need is a shutter speed that makes sure there is enough light to correctly expose the photo?
Well the control of shutter speeds allows you to control the image in such a way that two photos of the same subject shot at different shutter speeds would look vastly different. There are also shots that you would never be able to achieve without the control of, for example, the bulb setting.
This image again shows movement as the background and foreground but the car is frozen, this is achieved with shutter control and good panning. İAshley Beolens http://www.fatphotographer.net
Not every photo must be pin sharp, in fact to add movement (or the impression of movement with a term known as motion blur) a slower shutter speed is required, usually along with a good panning action or some other technique (placing the camera and subject on a moving object etc.).
As alluded to above sometimes very long exposures are needed to create stunning firework images, or car light trails or star trails moving across the sky, without shutter control many of these things would not be possible. Likewise images of frozen athletes mid leap or birds wings would not be achievable without controlling shutter speeds.
As you can see there are a lot of determining factors and it is not always as simple 1 plus 1 equalling 2 (photography tends to be like that), but hopefully I have given you some deeper insight into your shutter (and some further reading), and it will help move your photography forward.
As always I love to hear if my tutorials have helped in anyway so please get in contact if you have found this useful (or not I am open to criticism equally).
This site was last updated on Monday, 15th February 2016.
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