So over the next couple of weeks we'll take a look at things like shutter, aperture, ISO and other basic camera functions.
Today we will discuss the camera's shutter.
The camera's shutter is essentially a curtain that allows light to pass through for a set amount of time. Different cameras have different options, but commonly one can choose options between 1 second and 1/500th of a second. Many cameras have a larger range of options than that, and some have fewer. Bulb is another common feature, which allows the shutter curtain to remain open for as long as the shutter release button is pressed.
Each change either doubles or halves the light allowed to enter the camera. A 30-second exposure allows half the light of a one minute exposure. A 1/125 second exposure allows double the light of a 1/250th exposure. A 1/15th second exposure allows half as much light as a 1/8th second exposure. A 1/30th second exposure allows double the light of a 1/60th second exposure. You get the idea. Also, to complicate things, some cameras have intermediate options between the standard shutter speeds.
Note that many cameras delete the "1/" from the fraction, and will show (for example) 250 instead of 1/250. Sometimes shutter speeds of one minute or more are shown with a single quotation mark, like this: 1".
The choice of shutter speed depends on how you wish to capture movement. If there is no motion in what you are photographing, then the shutter speed makes no difference. Well, that is true to a point. You can only go as slow as 1/60th of a second (or 1/15th of a second if you have image stabilization) before you will need a tripod to prevent camera shake.
If you want movement to be blurred, you want to use a slow shutter speed. If you want movement to be sharp, you want to use a fast shutter speed.
Here's what I mean:
|River And Tree|
This 1/8th second exposure makes the fast-flowing river a silky blur.
This 30-second exposure shows the movement of the flag in the wind.
Cajon Pass, California
This 1/8th second exposure makes the train a blur.
|Motion Of Rock|
Using a 1/10th second exposure made the guitar player blurred.
A 30-second exposure captures the movement of the fireworks as streaks of color.
Apache Junction, Arizona
I only needed a 1/30th second exposure to make the fast motorcycle blur.
|Road And Hills|
This was a 30-second exposure.
Note that in most of the above photographs a tripod was used to prevent camera shake.
|Union Pacific Trailer Train At Mormon Rocks|
Cajon Pass, California
A 1/250th second exposure was used to ensure no blurring of the moving train.
|Around The Bend|
A 1/500th second exposure was used so the moving train would be sharp.
|Dam And Lake|
Hoover Dam, Nevada/Arizona
Using a 1/250 second exposure allowed me to capture the ripples on the lake.
A 1/500th second exposure was used to capture the movement as a sharp image, instead of a blur.
|Geese In A Row|
This was a 1/125th second exposure.
|Boy With Flag, Riverside National Cemetary|
A 1/500th second exposure was used to capture the running boy as a sharp image.
When you think about what shutter speed is most appropriate, consider what movement you are trying to capture and what you want that movement to look like. If you want it blurred, choose a longer exposure. If you want it sharp, choose a shorter exposure.
We'll discuss shutter speed again later, specifically how it relates closely with aperture and ISO.
Next time we'll talk about aperture.