When it comes to determining your exposure in Manual mode, there are three settings that you have to know: aperture, ISO, and shutter speed. Last Friday, we talked about aperture, so today we’ll be talking about shutter speed.
What is shutter speed?
To put it in the simplest of terms possible, shutter speed is the amount of time the shutter stays open to take a picture.
But what’s the “shutter”? you ask.
The shutter is located behind the mirror (and, often, the light meter) of your camera. Digital cameras feature two shutters that kind of look like black curtains. To let light in, these “curtains” must open and close when you take a picture.
When you select a shutter speed, you are selecting how fast these “curtains” are opening, or the speed that your camera will need to capture your picture.
Extending the curtain metaphor a bit further, when taking a picture, your camera first opens the aperture to the right size for that exposure. Then, it removes a cover from in front of the sensor to allow the light to reach it. Once the exposure time has been completed, the camera moves the shutter back in front of the sensor, blocking any more light from reaching the sensor.
Shutter speed, like aperture, is measured intervals (usually, fractions of a second) that are common to all cameras.
Why Does Shutter Speed Matter?
Along with being important in helping you get the kind of exposure you want in a picture. Shutter Speed is important in helping you have more creative control over your images.
When determining your shutter speed, you must first determine what’s most important for your shot. How important is movement in your picture? How important is focus? How important is detail? A slower shutter speed is one in which the shutter stays open for a longer amount of time, so these speeds are ideal for capturing movement. The higher shutter speed is one in which the shutter is open for a short amount of time. Short amount of time = better for freezing motion.
In the pictures below, I wanted to capture the movement of my daughter’s skirt as she danced. For dramatic effect, I first used a shutter speed of 1/13, which is pretty slow.
I liked the artfulness of the movement of her skirt at this speed, but I wanted more detail, so I bumped up my shutter speed to 1/30.
This was better, but I still didn’t like the amount of blur in the shot, I went up, again.
The shutter speed in this shot is 1/125. There’s still some blur, but I didn’t mind it as it conveyed my artistic vision. As a trade off, I had to bump up the ISO in this shot to allow more light in.
How Do Aperture and Shutter Speed Work Together?
Before I go into how aperture and shutter speed work together, let’s return to our definition of aperture.
The size of the opening of your lens when a picture is taken. The opening is what allows light to enter your camera.
Okay, now let’s go back to our definition of shutter speed.
Shutter speed is the amount of time the shutter stays open to take a picture.
Aperture and Shutter speed work on the same principle: When you move up or down either scale, you are doubling or halving the amount of light let into the camera.
Every time you move from one shutter speed to the next, you are either doubling or halving the amount of light that is being allowed in to the camera. So, as with my examples, when I upped my shutter speed, I could have increased my ISO or aperture to allow the same amount of light to enter the camera as when I was using a lower shutter speed. Changing my aperture would have changed my depth of field, and I had enough light available, so I choose to increase my ISO.
For your homework today, I want you to practice using shutter speed on your camera. Experiment with different subjects and different speeds to see what you can come up with!
Okay, now that you know the basics of shutter speed, let’s go one step further on Friday and talk about something called exposure compensation.