Cafe Art & RPS Mentoring Group

WHAT IS SHUTTER SPEED

Every camera has a physical shutter, like a curtain, that opens and closes to expose the sensor to the light coming in through your lens when you press the shutter button.  The length of time that this shutter is open is called the shutter speed and also sometimes referred to as ‘exposure time’.  Shutter speed is one of the three sides of our exposure triangle, along with aperture and ISO, that allow us to control the brightness of our image.  These three things work together to give us both creative control and also exposure control for our photos.  We can select a fast shutter speed that freezes any action in a photo, or we can select a slow shutter speed that introduces ‘motion blur’ to any moving objects within our image.

Combining a panning motion of the camera (left to right, or right to left movement) with a slow shutter speed can be used to give a sense of speed, as in the car photo below.  It gives a sense of movement to the car, but doesn’t blur out any of the car’s detail if you keep the car in the same spot in the frame as you pan.  With the running water in the photo below, the static camera but blurry water gives the water a sense of fluid motion.  When you are taking a photo with your camera in a semi-automatic Aperture or shutter speed mode or manual exposure mode, then consideration must be given to the required shutter speed for your subject.  Most of the time we are looking to freeze our subject with a fast enough shutter speed and capture that one singular moment, but sometimes the creative effect of a slower speed can also be desirable.  What shutter speed is fast enough? Well that will depend on your subject!  Further down this article there’s a handy reference guide that’ll get you started with some typical scenarios.

HOW IS SHUTTER SPEED MEASURED?

A camera’s shutter speed is measured as a fraction of a second for all speeds that are under a second.  For example 1/250 means one two hundred and fiftieth of a second, or 1/8 means one eighth of a second.  The shutter speeds that are available to choose from might vary depending on the type of camera you are using, Anything from 1/8000 all the way to 30 seconds. Many will also have ‘BULB’ mode for shooting at longer than 30 seconds. This mode keeps the shutter open for as long as you hold down the shutter button.

If you double your shutter speed then the shutter will be open for half the amount of time so you half the amount of light that’s reaching the sensor. This is therefore equivalent to a 1-stop change in exposure.  To maintain the same overall exposure in our image, we must remember the exposure triangle and either double our ISO, or open up our aperture by one stop to compensate.

SHUTTER SPEED GUIDELINES

The following table will give you some general guidelines.  It’s important to remember though that there’s very rarely any concrete ‘rules’ in photography as part of the whole process comes down to your own style and creativity.  On top of this, other techniques often come into play and the image of the race car is a good example of this.  This is a  specific technique called ‘panning’ with a  lower shutter speed to give a sense of how fast the car was going.

Remember: Use this table as a starting point, but by no means is anything set in stone.  Don’t let it hold back creativity!

HOW TO GET A FASTER OR SLOWER SHUTTER SPEED

Sometimes you’ll find that the ambient lighting conditions appear to be holding you back from choosing the shutter speed that you really want to use.  This is when we really need to think about that exposure triangle of aperture, shutter speed and ISO.  To get the longest exposure time possible in bright daylight, we need to have the lowest possible ISO and the smallest possible aperture.  If that still doesn’t get your shutter speed slow enough show the motion you want in your photo, then you need to look at using a neutral density filter on your lens.  This filter doesn’t apply any special effects, it simply darkens the lens and with less light coming in, you’re able to shoot with a longer shutter speed to get the correct overall exposure.

On the other end of the spectrum, if you are struggling to get a fast enough shutter speed, typically in a low light situation like indoors or after the sun has gone down, then you’ll need to open up your aperture as far as it will go (move it to the smallest number).  If this still doesn’t get your shutter speed up to the necessary setting, then you’ll need to increase your ISO.  Remember the exposure triangle and how everything doubles.  If you double your ISO, you’ll be able to double your shutter speed and still maintain the same overall exposure.

TRIPODS

it’s not possible to experiment with some of the speeds we’ve talked about in this article without a tripod.  The speed at which you’ll need to use one will depend on both the focal length you’re shooting at, and also whether your lens has image stabilization or not.  Many lenses/cameras have a 4 or 5  stop image stabilization and this means that you can shoot at much slower shutter speeds than you would be able to without IS.  This can make a big difference.

A general rule of thumb that you’ll often hear referred to is that your camera will require some additional support when you shutter speed needs to be less than 1/[Focal Length]. So if you are shooting with a 50mm lens, you might consider using a tripod if you are experimenting with shutter speeds that are less than 1/50 second. Again, stabilization might come into play, as will your own technique, for holding the camera steady.  For very long shots like start trails and photos with running water in them, a tripod is going to be a necessity though.  

Content taken from Shuttermuse.com