Intentional camera movement (ICM)

Learning goal

You will be able to turn a sharp scene into a painterly image by moving the camera deliberately and in a planned way while the shutter is open. You will tell this technique apart from the unwanted blur that comes from a shaking hand and from panning, which follows the subject, and choose the direction of movement according to the scene's dominant lines. You will know which range of shutter speeds is used as a starting point, and calculate how many stops of ND filter are needed to reach a half-second exposure on a sunny day. You will try different movements, such as vertical drag, zoom burst and rotation, balance the trails by pressing the shutter in the middle of the movement, and choose from among many attempts. In frames with people in them, watching how faces scatter and how skin mixes with the background, you will be able to keep a face sharp with rear-curtain sync when needed. You will discuss whether a frame is art by looking not at a single rule but at intention and consistency.

The question

On the bank of the stream there is a long row of poplars. The trunks are bolt upright, whitish and slender; yellow leaves and the green meadow behind show between them. Your friend from the club describes a photo they saw at an exhibition: trees of the same kind had turned into light and dark strips running from top to bottom instead of sharp lines, and the leaves had flowed between them as yellow patches. At first glance it looks like a watercolor. The person who shot it had lifted the camera toward the sky in a planned way while the curtain stayed open.

Your friend tries once. The camera in their hand, a half-second shutter speed, they pull the camera upward. The first frame is a blurred green scattered in every direction; in the second the trunks are slightly crooked. On the tenth attempt the strips are upright, and the leaves sit between the trunks like soft lights. Your friend looks at the screen for a long time and stays undecided: is this blur an accident or a choice? Can shaking the camera be art?

Context

In the frozen moment and flowing motion lesson we defined panning as following a moving subject with the camera to show the subject sharp and the background streaked (Lesson 8.5). In that technique the movement has a purpose: keeping the subject sharp. Intentional camera movement leaves this purpose behind. It doesn't try to keep anything sharp; it redraws the whole scene with movement.

Most of photography is built on focus, sharpness and freedom from shake, and most of the lessons so far taught how to prevent blur. This lesson looks from the opposite direction: what happens when blur isn't a flaw but a brush used deliberately? The answer depends less on whether you like the result than on how controlled the movement is and what it is used to say.

Simple explanation

How is it different from shake?

Intentional camera movement (ICM) is deliberately blurring the scene's lines and colors by moving the camera in a planned direction and at a planned speed while the shutter is open. The difference between it and the blur that comes from a shaking hand is intention, but intention alone isn't enough. Shake is random: edges scatter in every direction, no line is preserved, and the result can't be repeated. Intentional movement, on the other hand, has a direction: some of the scene's lines stretch along the movement and are preserved, while others melt away.

The scene's dominant line decides the direction of movement. In a scene full of vertical lines, like bolt-upright tree trunks, if the camera is moved parallel to the trunks, that is, up or down, the trunks turn into long strips but stay separate from each other. In the same scene, if the camera is pulled sideways, the trunks mix into each other and the vertical structure is lost. If there is a horizontal structure, like the horizon line at the seaside, a horizontal movement separates the sea, the sand and the sky into three strips of color.

Vertical drag is moving the camera up or down at a steady speed throughout the exposure. This is the most commonly used movement in forests and tree rows where vertical lines dominate, and it is a good start for getting to know the technique.

What shutter speed, what light?

How much of a trail the movement leaves in the frame depends on the length of the exposure and the camera's speed. As a starting point, between one fifteenth of a second and one second is often used. At the short end shapes are still recognizable and only the edges soften; at the long end forms turn into fields of color. At the same shutter speed, pulling the camera fast leaves longer trails, and pulling it slowly leaves shorter ones. These values aren't templates, but points to start experimenting from.

In daylight, a curtain this slow requires cutting down the light. According to the sunny 16 rule, on a sunny day at ISO 100 and f/16 the shutter speed is about one hundredth of a second (Lesson 19.5). Lengthening this to half a second means reducing the light fifty times, that is, about six stops; a six-stop ND filter takes the shutter speed to a little over half a second. On a cloudy day, at dusk or in a shady forest, less filter is enough or none is needed.

When the shutter is pressed matters too. If you shoot with the camera still and then move it, a sharp image and its stretched trail overlap somewhere in the frame. Starting the movement before pressing the shutter and continuing until the exposure closes spreads the trails evenly across the frame.

There are movements besides vertical drag too. A zoom burst is quickly changing a zoom lens's focal length while the shutter is open, and the image spreading outward from the center like rays. The subject in the center stays relatively distinct while the surroundings flow like an explosion. Putting the camera on a tripod keeps the center steadier; a zoom burst done handheld gives a more scattered result.

Rotation is turning the camera around the lens's axis throughout the exposure, and the image turning around the center like a whirlpool. In the middle of a flower or under a dome, this movement turns the scene into a spiral.

Apart from these, the camera can also be moved by drawing an arc, with a small vibration, or with the rhythm of a walk. Whichever movement is chosen, this technique takes dozens of attempts. The same movement gives a slightly different frame each time; as you discussed in the culling lesson, setting aside the few most consistent frames at the end of the shoot is part of the job (Lesson 17.3).

What changes if there are people?

A movement made through a crowd or around a dancer turns people into patches of color, and faces become unrecognizable. In street photography this can be a way of showing a movement or the energy of a crowd while hiding identity.

Skin mixes with the background's color in a blurred frame. When the movement stretches a face, a bright background spreads toward the edges of the face. Dark skin in front of a bright sky can turn gray at its edges with this spreading and lose its color; light skin in front of a dark background, on the other hand, stretches and leaves a whitish halo on the background. If you want the color preserved, choosing a background of similar brightness to the skin or keeping the movement short helps.

If a face should stay sharp, flash comes into play. Rear-curtain sync is the flash firing not at the start of the exposure, but just before the curtain closes. Throughout the movement the ambient light draws soft trails; the flash freezes the face sharply at the end, and the trail stays behind the face. In this case it is not the shutter speed but the flash's power that decides the face's exposure; for dark skin, raising the flash power a little or bringing the flash closer lets the face show in the right tone among the trails.

Art or mistake?

Technique alone doesn't decide whether a frame is art. A photo shot with a shaking hand and a photo shot with a planned movement are both blurred. But in the second, the photographer chose the direction of movement according to the scene, set the shutter speed, was able to reproduce the result, and chose deliberately from a series. This control takes a frame out of being an accident. In the history of painting, the brushstroke itself is seen as a means of expression; in photography, the trail of movement can take a similar place, but this is a claim and the frame itself has to carry it. At the same exhibition, one viewer may be moved by strips reminiscent of watercolor while another sees only a blurred forest; both are legitimate reactions. Whether the resulting image is found impressive is up to the viewer; what this lesson gives you isn't a rule of taste, but the tools to use blur deliberately.

Visual evidence

On a sunny morning you stand in front of the row of poplars. With ISO 100 and f/16 the reading is around one hundredth of a second; when you attach a six-stop ND filter the shutter speed rises to a little over half a second. You hold the camera in your hand, parallel to the trunks, start a movement from bottom to top first, and press the shutter in the middle of the movement.

In the first frames the movement goes slightly crooked and the trunks look tilted. After a few attempts the movement becomes steady: the whitish trunks are long, upright strips; between them the yellow leaves are soft patches; at the bottom edge the meadow's green is a horizontal band. When you pull the camera sideways in the same scene, the trunks mix into each other and the tree row turns into an unrecognizable green-yellow field.

Your friend stands in front of the trunks; the bright sky is behind their face. You set the flash to rear-curtain sync and bring it a little closer. While the trails of the movement flow around your friend, the warm brown of their dark skin is sharp and in the right tone; the trails stay behind the face.

Common mistakes

Summary

Intentional camera movement deliberately blurs the scene by moving the camera in a planned direction while the shutter is open; the direction of movement is chosen according to the dominant lines, between one fifteenth of a second and one second is a starting point, and in daylight an ND filter is needed for such a slow curtain. Vertical drag, zoom burst and rotation leave different trails; the movement is started before the shutter, and a choice is made from dozens of attempts. In frames with people, faces scatter and skin mixes with the background, and if a face needs to stay sharp, rear-curtain sync is used; whether a frame is art is debated not by a single rule but by how controlled the movement is and what it is used for.

Mini assignment

In this assignment you will try intentional camera movement in a scene where vertical lines dominate, in front of a row of trees, a fence or a building.

1. Calculate how many stops of ND filter are needed for a half-second shutter speed in your light, or choose a time of day when the light is already enough.
2. In the same scene, move the camera once parallel to the lines and once perpendicular to them, and compare the results.
3. Shoot at least thirty frames; experiment by changing the shutter speed and the speed of movement, and in the end choose the three most consistent frames.
4. If there is a person in the frame, note how the skin mixes with the background; if you have a flash, try keeping the face sharp with rear-curtain sync, and check the face's tone.

Check yourself

• Can you explain what separates intentional movement from a shaking hand and from panning?
• Can you justify the direction of the movement you chose with the scene's lines?
• If there was a person in the frame, did you check whether their skin kept its color?

Glossary

Mini quiz

1. In a scene full of vertical lines like poplar trunks, how is the camera moved to show the trunks as long, separate strips?

• A) Sideways
• B) Diagonally
• C) Up or down
• D) It isn't moved

2. On a sunny day at ISO 100 and f/16 the shutter speed is around one hundredth of a second. About how many stops of ND filter are needed to get down to half a second?

• A) Six stops
• B) One stop
• C) Three stops
• D) Ten stops

3. A sharp image of the same scene also appears on top of the blurred trails. What is the most likely cause?

• A) The ND filter is too strong
• B) The shutter speed is too long
• C) The direction of movement is wrong
• D) The shutter was pressed with the camera still and the movement was started afterward

4. A dark-skinned person's face in front of a bright sky turns gray with the movement, and the face should stay sharp. Which is the most suitable approach?

• A) Lengthening the shutter speed
• B) Using flash with rear-curtain sync and setting its power for the face
• C) Speeding up the movement
• D) Switching to a zoom burst

Answers

1. C — When the movement is parallel to the lines, the trunks stretch but stay separate from each other.
2. A — From one hundredth of a second to half a second is fifty times; that makes about six stops.
3. D — The short still moment records a sharp image; the movement should be started first.
4. B — Rear-curtain sync freezes the face just before the curtain closes; the face's tone is set with the flash power.

Summary card

• Choose the direction of movement parallel to the dominant lines.
• Between one fifteenth of a second and one second is the start; in daytime an ND is needed.
• Start the movement first, press the shutter in the middle.
• Shoot dozens of frames, choose the most consistent.
• If there are people, check the skin against the background; if the face is to be sharp, use rear-curtain sync.

Bridge to the next lesson

In the evening at the club, while your friend's poplar frames were on the screen, an older member took an old print out of their bag. A tree row of the same kind, but the leaves snow white, the sky almost pitch black, the stream's water dark as ink. They said they had shot the photo not in winter but in summer, on a day full of green leaves; they had attached a filter to their camera that records a light the eye can't see. Why do the leaves look white? The next lesson tells about photographing invisible light with an infrared filter or a camera converted for this light.