Today we are going to define and discuss one part of exposure. After this lesson, you should know what shutter speed is, how it works inside your camera, and how changing your shutter speed affects your photographs.
BUT FIRST-What is exposure?
Inside your digital camera, there is a little sensor. The sensor is exposed to light. The goal is to expose the sensor in your camera to the correct amount of light. If the picture is overexposed, it means that the sensor was exposed to too much light making the photo too bright. If the picture is underexposed, it means that the sensor wasn’t exposed to enough light, which results in an image that is too dark. Our goal in beginning photography is to expose the sensor correctly. We want to be able to see all the detail in the photo-nothing too bright or too dark.
To better understand the idea of exposure, you need to know more about the parts involved. There are three parts to exposure: shutter speed, aperture, and ISO. For this lesson we will only be focusing on shutter speed.
Think of shutter speed like your eyelid. You can control how long the your eyelid stays open. The same idea happens inside your camera. The shutter-like your eyelid-“blinks.” Some blinks take longer than others. You are in charge of how long or short you’d like the “eyelid” (or shutter) to be open.
When you think of shutter speed, think of two things: Motion and Light.
Shutter speed determines motion.
Shutter speed determines how much motion is captured by the sensor. Ok, so what in the world does that mean? I’ll show you. In the photo below, you notice that the cream is falling into the cup in a blur of motion. It isn’t a nice detailed line of cream; it’s more smooth, and shows the movement of how the cream fell into the cup. When the shutter inside your camera (think eyelid;-)) is open for a longer amount of time, the motion is captured in a blur. The “eyelid” is open longer so the sensor is able to capture all the movement from the creamer. The opposite is also true. The shorter amount of time the shutter is open, the less motion will be captured.
Shutter speed determines light.
Shutter speed also affects the light in the photograph. When the shutter is open for a long period of time, more light is allowed to reach the sensor. So the longer the shutter is open, the brighter the image; the shorter the shutter is open, the darker the image.
So this is what you need to remember:
When thinking of shutterspeed, think of 2 things: Light and Motion. Here are the relationships you need to know.
LONG SHUTTERSPEEDS mean more light and more motion in your image(but be careful of blurring the photo.)
SHORT SHUTTERSPEEDS mean less light and less motion in your image. (sharp lines, crisp edges in the photo.)
Measuring Shutter Speed
You measure shutter speed in fractions of a second. The shutter speed of 1/30 is slower and open longer than the shutter speed of 1/4000. What you want your image to look like has a big impact on what your shutter speed should be. Some questions I ask myself when setting my shutter speed: Do I want my image to be sharp or do I want to capture motion? If I want to capture motion then my shutter speed will be longer. If I want my image sharp with crisp lines then I want my shutter speed to be shorter. I recommend you memorize some common shutter speed settings. This chart on Pinterest is a great reference.
Test Your Knowledge
What kind of shutter speed (long or short) would you set your camera to if you want to show the motion of a runner crossing the finish line? Tell what shutter speed would you set your camera to if you wanted to capture a flat lay for your blog? What kind of shutter speed would you use if you wanted to capture the water flowing through a stream?
For homework, look at some photos online. Pinterest is a great resource. Ask yourself what kind of shutter speed you would use in order to get the same image? Or maybe you’d want the image totally different. How would you change your shutter speed in order to get the opposite effect?