vibration reduction

8/8/2019 Vibration Reduction

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Vibration Reduction (VR) system compensates for image blur caused by

small, involuntary movements (from wobbly hands, shooting from a

moving vehicle, etc) which are called camera shake. This system can be

found in many Nikon products, such as interchangeable lenses for SLR

cameras, digital cameras and binoculars. In this issue, the principles of

VR will be explained by using an interchangeable SLR lens as an example.

Fig. 1 shows how the light from subject (A) reaches focal plane (A)

through the lens.* Without camera shake, light from A converges at A.

However, if the camera's lens moves up or down (ie. camera shake see

arrow) the light from A will converge on A. This gap results in imageblur. The VR System works by adjusting the lens to compensate forcamera shake and to make sure light from A converges on A. Each VR

Unit contains a VR lens elements and driving motors to make this happen.

*(For the sake of simplicity, this diagram shows only one lens element. In actuality, an

interchangeable VR lens has many lens elements.)Fig. 1

Fig. 2

To compensate for image blur caused by camera shake, the angular

velocity (amount of camera shake) should be detected accurately. Two

angular velocity sensors are used in the VR System. One detects

"pitching" (vertical movement), while the other detects "yawing"


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(horizontal movement). Diagonal movements are detected by combining

the results of both sensors. These sensors detect camera movement as

angular velocity every 1/1000 second. Angular velocity data is sent to a

microcomputer built right into lens, which then calculates the amount of

compensation needed. After this data is transmitted to the VR unit, the

adjustments are made instantaneously. (Fig. 2)

The built-in microcomputer calculates the amount of lens movement

necessary using data from the angular velocity sensors. Commands are

sent to two VCMs (Voice Coil Motors), which move the VR lens in a

particular direction. This is controlled by the electric current inside theVCM's magnetic field. One motor controls the vertical, while the other

controls horizontal, with both working together to compensate for

diagonal movement.

With most interchangeable VR lenses, VR operation is activated by lightly

pressing on the shutter release button. When a photographer is

recomposing a picture while keeping the shutter release button halfpressed, the system can instantly tell whether camera movement is

intentional or caused by camera shake and act accordingly. For example

VR does not compensate for recomposing movement that camera

movement, because if it did, the photographer could have difficulty

accomplishing the desired composition.

Nikon's VR System changes operation algorithms when the shutter

release button is lightly pressed and during exposure. Therefore, when

the shutter release button is lightly pressed, the VR lens gives you a

smooth viewfinder image. During the exposure, however, the algorithm

changes to compensate for every slight movement. What's more, justbefore exposure, the VR lens will reset to central position (optical axis)

from an off-centered position which is a result of VR operation during the

shutter release button is lightly pressed. Since the shift amount of the VR

lens is limited, this operation maximizes VR effects as well as opticalperformance. Only Nikon has this "Centering Before Exposure" feature.

(Fig. 3)

Image blur caused by camera shake generally occurs with shutter speeds

slower than 1/[focal length] in 35mm format equivalent. Nikon's latest

VRII lenses offer the ability to shoot at shutter speeds 4 steps faster. Fig. 3


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*Simulated image.

When the AF-S DX VR Zoom-Nikkor 18-200mm f/3.5-5.6G IF-ED is used

at 200mm focal length: A photographer shooting at a 1/125 secondshutter speed may avoid camera shake 70% of the time. By using the VR

system, he or she can achieve the same results at a speed of 1/8 second

(4 steps slower than 1/125 second: 1/60-1/30-1/15-1/8)*.

*Effect of VR System varies by photographer.

In addition to the "Centering Before Exposure" System, Nikon's VR

System offers Normal mode and Active mode, original technologies to

help you cover various shooting situations. In Normal mode, slow and

wide camera movement is regarded as recomposing movement and VR

operation is controlled accordingly. In Active mode, however, even large

amounts of camera movement are compensated for to give a smooth

viewfinder image. This mode is quite useful when shooting from a moving

vehicle or some other unstable position.

A tripod is generally believed to prevent image blur, but camera shake

can occur due to the movements of the quick-return mirror or shutter

curtain, or winds. This camera shake movement has differentcharacteristics compared to normal camera shake caused by handheld

shooting. Nikon's VR technology makes it possible to detect and

compensate this type of camera shake, as well. (Note: Some VR lenses do

not have this function.)


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Nikon has developed its original VR technologies by rigorously studying

the various aspects of camera shake. Renewed March 2008

vibration reduction

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