Shutter speed

Learning goal

You will be able to define shutter speed as the time the sensor stays open to light. You will read values written on the camera such as 1/250 or 2", work out what shortening or lengthening the time by one step does to the light, explain that this time also decides how movement will look, roughly work out the longest time you can safely shoot handheld, recognize the difference between a mechanical and an electronic shutter and the bands caused by lamp flicker, and strike the balance of gathering enough light in dim light without blurring faces.

The question

Have you ever seen a photo that shows water drops thrown into the air by a child as if hanging in the air like glass beads? Or a photo where the headlights of cars crossing a bridge at night have turned into long red and white streaks? The only setting that separates the two frames is the time the sensor is kept open to light. The drops carry a moment shorter than a thousandth of a second; the light streaks carry a flow of a few seconds.

How do we freeze time? The answer is hidden in deciding how long the shutter stays open when you press the shutter button. In this lesson we will talk about how shutter speed is read, how it changes light, which time is safe when shooting handheld, and what surprises the shutter of modern cameras sometimes brings.

Context

In the bucket comparison, the shutter speed was how long the tap stayed open. The aperture set the width of the tap and changed the slice of sharpness; the shutter speed sets the time and changes movement. In Lesson 3.6 you told apart two kinds of blur: the whole frame shifting because the camera shakes, and only the subject blurring because the subject moves. The shutter speed is the main setting for both kinds of blur.

In Turkish this setting is called "enstantane", from the French word "instantané", meaning instant. In the first years of photography you had to wait for minutes for one photo; being able to take an "instant" photo was a revolution. In English this setting is called "shutter speed". On cameras the shutter speed is chosen with a dial or from a menu, and on phones in pro mode. By the end of this lesson you will be able to say in advance what will change in the photo when you turn that dial.

Simple explanation

How is shutter speed read?

Shutter speed is a time in seconds and is usually written as a fraction. 1/250 means a two-hundred-fiftieth of a second; 1/60, a sixtieth of a second. On some cameras only the bottom part of the fraction is shown: if the screen says 250, this is 1/250. Times of one second and longer are usually written with a quotation mark: 2" is two seconds; 30" is thirty seconds. The bigger the bottom number, the shorter the time.

Shutter speeds, like apertures, move in a series, a shutter speed scale: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15 and up to one second. Moving one step along the scale halves the time, and so the light gathered too; coming one step back doubles it. Going from 1/125 to 1/250 halves the light, and going to 1/60 doubles it. Each full step in aperture and each full step in shutter speed make the same amount of change in light; that is why when you close one by a step, you can keep the same brightness by opening the other by a step. Many cameras also add two in-between values between these steps, for example 1/160 and 1/200.

How does time change movement?

As long as the shutter stays open, the sensor records everything happening in the scene. If the time is very short, for example 1/1000 or shorter, almost nothing can move in that time; a running child, a flying bird, splashing water drops look frozen. As the time grows longer, everything that moves leaves a trace on the sensor: a walking person's legs blur, the water of a flowing stream softens, the headlights of passing cars turn into lines.

The same time also records the camera's own movement. A camera held in the hand is never completely still; as the time grows longer, this small shake becomes visible across the whole frame. That is why, when choosing the shutter speed, you ask two questions together: how fast is the subject moving, and how steadily can I hold the camera? Freezing movement or letting it flow on purpose is a storytelling decision and the subject of the next lesson. In this lesson we will first build the measure for avoiding unwanted blur.

What time is safe handheld?

When shooting handheld, there is an old, rough measure photographers use: the shutter speed shouldn't be longer than one over the focal length of the lens. With a 50-millimeter lens, at least around 1/50; with a 200-millimeter lens, at least around 1/200. The reason is simple: a long lens enlarges a small part of the scene and enlarges the small shake of the hand by the same amount. On cameras with small sensors the frame is narrower, so shifting this measure to a slightly shorter time is safer. This gives you a rough safe handheld shutter speed.

This measure isn't exact; it only gives a starting point. Image stabilization, the supported grip you learned in Lesson 3.6, and leaning on a wall or a table let you take sharp photos at longer times too. But stabilization only reduces the camera's shake; if the subject is moving, it doesn't help. When photographing people, especially children or someone talking, 1/125 or shorter is a safe lower limit, regardless of stabilization, to stop small movements from softening the face.

What surprises do the shutter and lamps bring?

Cameras have two kinds of shutter, and the difference between a mechanical and electronic shutter matters. A mechanical shutter is a thin curtain that really opens and closes in front of the sensor. An electronic shutter, on the other hand, doesn't use a physical curtain; it switches the sensor on and off and reads it line by line. Almost all phones use an electronic shutter. An electronic shutter is silent and can give very short times; but because of the line-by-line reading, it can show very fast-moving subjects tilted or bent: a spinning propeller can turn into odd curves, and a train rushing past into a box leaning to the side.

Lamps can bring surprises too. Many lamps running on mains electricity, especially some LEDs and fluorescents, flicker at a speed the eye doesn't notice. This light flicker means a very short shutter speed can coincide with the dark moment of the flicker, or with an electronic shutter it can create horizontal light and dark bands across the photo. When these bands pass over a face, they divide the skin into zones and make the color and brightness uneven on both dark and light skin. In Türkiye, as in most of Europe, mains electricity runs at fifty cycles a second, so many lamps flicker a hundred times a second and the flicker follows this rhythm; if you see bands like these indoors, lowering the shutter speed to 1/100 or 1/50 usually solves the problem.

Visual evidence

In the evening, you photograph a grandfather playing backgammon in a dim coffeehouse with a camera. The only light is a yellow bulb hanging from the ceiling. First you shoot handheld at 1/15. The whole frame looks slightly doubled: the edges of the backgammon board, the tea glasses and the grandfather's face have all shifted in the same direction. This is your hand shaking.

Then you rest your elbow on the table and shoot again at 1/15. The board, the glasses and the clock on the wall are sharp. But the grandfather's hand throwing the dice and his fingers sliding the pieces are blurred like a smudge; his lips, moving as he talks, have softened too. Now the camera is steady, but the subject is moving. Finally you open the aperture, raise the ISO and shorten the shutter speed to 1/250. The dice are frozen in the air, and the grandfather's smiling face, his skin darkened by the sun and the hair-by-hair lines of his mustache are sharp. Three frames, three times; the source of the blur is different each time.

Common mistakes

Summary

Shutter speed is the time the sensor stays open to light; it is written as fractions such as 1/250 or as seconds such as 2", and each full step on the scale halves or doubles the light. The same time also records every movement in the scene and in the camera: a short time freezes, a long time leaves a trace. The safe handheld time is roughly one over the focal length, and 1/125 is a good lower limit for moving people; an electronic shutter can bend fast subjects, flickering lamps can create bands across faces, and to gather light in dim conditions without blurring the face, the time has to be balanced together with the aperture and ISO.

Mini assignment

In this assignment you will choose the time by hand and compare the results; you need S mode on your camera or pro mode on your phone.

1. Standing in the same spot, photograph a still object handheld at 1/250, 1/60, 1/15 and 1/4, and find where the frame starts to shake.
2. Try the same times while leaning on something or supporting both hands with your elbows, and note how much longer the safe time gets.
3. Photograph a friend talking or gesturing with their hands at 1/30 and 1/250 and compare the difference in the face and hands.
4. In an interior with LED or fluorescent light, shoot at a very short time; if you see bands, lower the shutter speed to 1/100 or 1/50 and try again.

Check yourself

• Did you find, by your own measurement, the longest time you can shoot safely handheld?
• In a blurred frame, can you tell whether the problem is the camera shaking or the subject moving?
• Did your friend's face come out sharp and without bands, without the color and texture of their skin being spoiled?

Glossary

Mini quiz

1. What does a shutter speed written as 1/250 on a camera mean?

• A) Two hundred fifty seconds
• B) A two-hundred-fiftieth of a second
• C) Two hundred fifty milliseconds
• D) The size of the aperture

2. How does shortening the shutter speed from 1/125 to 1/250 change the light?

• A) It doubles it
• B) It doesn't change it
• C) It halves it
• D) It warms the colors

3. When shooting handheld with a 200-millimeter lens, by the rough measure, what should the shutter speed be at least?

• A) Around 1/200
• B) 1/15
• C) 1 second
• D) 1/30

4. What are horizontal light and dark bands passing over a face indoors a sign of?

• A) Wrong white balance
• B) Too much aperture
• C) Diffraction
• D) Flickering lamps being caught with a short shutter speed or an electronic shutter

Answers

1. B — Shutter speed is a fraction in seconds; 1/250 describes the sensor staying open for a two-hundred-fiftieth of a second.
2. C — 1/250 lasts half as long as 1/125; when the shutter stays open half the time, half the light fills the buckets.
3. A — A long lens also enlarges the shake of the hand; by the rough measure the time shouldn't be longer than one over the focal length.
4. D — Some lamps flicker at a speed the eye can't see; a short time or line-by-line reading turns this flicker into bands across a face.

Summary card

• Shutter speed is the time the sensor stays open to light: 1/250, 1/60, 2".
• Each full step halves or doubles the light.
• A short time freezes movement; a long time leaves a trace.
• Safe handheld time ≈ 1 / focal length; 1/125 is a good lower limit for people.
• An electronic shutter can bend a fast subject; for lamp bands, lower the time to 1/100 or 1/50.

Bridge to the next lesson

In this lesson you used the shutter speed to avoid unwanted blur. But the same setting, used on purpose, turns into one of the most powerful storytelling tools in photography: a short time leaves a drop hanging in the air, a long time turns a waterfall into silk. The next lesson treats these two paths, the frozen moment and flowing movement, as a creative decision.