Vibration Reduction

At 600 mm on the Nikkor Z 180-600mm f/5.6-6.3 VR, a kingfisher on a reed fills a generous part of the frame, and so does every tremor of my hands. An old rule of thumb says a hand-held picture at 600 mm wants a shutter speed of about 1/600 s. Late on a winter afternoon, the light under the willows might allow only 1/60 s at the aperture and ISO (the sensor's amplification setting) I am willing to use. That gap is a factor of ten, a little over three stops (a stop is one doubling, explained below), and closing it is the job of vibration reduction.

Vibration reduction, which Nikon abbreviates VR, is Nikon's name for image stabilisation: hardware that moves part of the camera or the lens to cancel the shaking of your hands while the shutter is open. Page numbers in parentheses point to Nikon's Z6III Reference Guide, edition 09, which matches firmware 2.00.

01.Why Shake Grows With Focal Length

The Lever Between Your Hands and the Sensor

Aim a laser pointer at a wall one metre away, then at a wall ten metres away. The same small wobble of your wrist moves the dot a few millimetres on the near wall and a few centimetres on the far one. The wobble is an angle, and distance turns that angle into a sideways movement. A lens does the same to the picture on the sensor, with the focal length playing the part of the distance to the wall.

Suppose, as an illustrative figure and not a measurement, that your hands let the camera drift at a steady 0.03 radians per second while the shutter is open. One radian is about 57 degrees, so that is roughly 1.7 degrees per second, a slow sag rather than a jerk. For angles this small, the distance the image slides across the sensor is very close to the focal length multiplied by the angle turned.

• At 50 mm and 1/50 s, the camera turns $0.03 \times \tfrac{1}{50} = 0.0006$ radians, and the image slides $50 \times 0.0006 = 0.03$ mm.
• At 600 mm and the same 1/50 s, the angle is the same, but the image slides $600 \times 0.0006 = 0.36$ mm, twelve times as far.
• At 600 mm and 1/600 s, the angle shrinks to $0.03 \times \tfrac{1}{600} = 0.00005$ radians, and the slide falls back to $600 \times 0.00005 = 0.03$ mm.

To see what that means on this camera, divide the sensor's width by the pixels across it. The sensor is 35.9 mm wide (p. 997), and a full-size picture from the whole sensor, which Nikon calls FX, is 6048 pixels wide (pp. 998, 1009). Each pixel therefore spans about $35.9 / 6048 \approx 0.00594$ mm, or 5.94 micrometres. A slide of 0.03 mm smears each point over $0.03 / 0.00594 \approx 5$ pixels, which vanishes in an ordinary print. A slide of 0.36 mm smears it over about $0.36 / 0.00594 \approx 61$ pixels, which spoils the picture at any size.

In a simple model that treats the hand as drifting steadily, rather than trembling back and forth as real hands do, write $f$ for the focal length in millimetres, $\omega$ (the Greek letter omega) for the rate at which the camera turns in radians per second, and $t$ for the exposure time in seconds. The camera turns through $\omega t$, and the blur on the sensor, $b$, in millimetres, is

$$b = f \, \omega \, t$$

Double the focal length and the blur doubles. Double the exposure time and it doubles again. Nothing about your hands has changed at 600 mm, but the lens magnifies what they do.

The Reciprocal Rule of Thumb

The formula explains a long-standing piece of advice: hand-held, use a shutter speed no slower than one over the focal length. That is 1/50 s for a 50 mm lens and 1/600 s for the 180-600 at its long end. Put $t = 1/f$ into the formula and the focal length cancels:

$$b = f \, \omega \, \frac{1}{f} = \omega$$

Numerically, $b$ in millimetres equals $\omega$, because putting $t = 1/f$ quietly mixes seconds with millimetres. Following the rule holds the blur on the sensor to the same small amount at every focal length, 0.03 mm with my illustrative hands, exactly as the 50 mm and 600 mm examples showed. I chose the drift rate to land there because photographers have long treated about 0.03 mm as the most blur a full-frame picture can carry and still look sharp in an ordinary print.

It is a rule of thumb, not a law. It assumes typical hands, a typical print and a typical viewing distance. Good technique or a small print lets you go slower, and a large print or a 100 per cent view on screen asks for faster.

The Z6III builds a version of the rule into Auto ISO. In modes P (programmed auto) and A (aperture-priority auto), choosing Auto for Minimum shutter speed lets the camera set, from the lens's focal length, the slowest speed it accepts before raising ISO, with faster speeds for longer lenses to keep shake out (p. 467), and ISO and Auto ISO covers it. Nikon does not give the formula, so I would not assume it is exactly one over the focal length.

What the DX Crop Does to the Rule

FX is the full 36 by 24 mm frame, the angle of view of a 35 mm format camera, and DX is a smaller area in its middle, about 24 by 16 mm (pp. 116, 1009). Nikon says multiplying a lens's focal length by 1.5 gives the approximate 35 mm focal length for the DX view (p. 116). Image Area and Crop explains the crop, so the only question here is what it does to the rule.

At 600 mm in DX, the view matches a 900 mm lens on full frame, since $1.5 \times 600 = 900$. The rule then asks for about 1/900 s, two thirds of the exposure time FX needed.

Yet on the sensor nothing has changed. At 1/600 s the image still slides 0.03 mm, about 5 pixels. What changes is the picture around those pixels. A full-size DX picture is 3984 pixels wide (p. 998) instead of 6048, so shown at the same size it is enlarged about $6048 / 3984 \approx 1.52$ times as much, and its blur with it. The rule tracks the blur you see in the finished picture, which is why it tightens. Cropping an FX file to the same framing later gives the same result.

02.Stops of Stabilisation

Each Stop Doubles the Time

Photographers measure light in stops, also written EV for exposure value, and one stop is a doubling or a halving. For shutter speed, one stop slower means an exposure twice as long, so 1/640 s becomes 1/320 s. A stabiliser's rating uses the same unit. A system worth $n$ stops lets you hold an exposure $2^n$ times as long as you could unaided and still get the same sharpness, under the test's conditions.

The ladder in the figure starts at 1/640 s, a little faster than the 1/600 s the rule asks of a 600 mm lens. Three stops double the time three times: 1/320 s, 1/160 s, then 1/80 s. Since $2^3 = 8$, the time has grown eight-fold, and $640 / 8 = 80$ confirms it. Five stops multiply it by $2^5 = 32$, and $640 / 32 = 20$, so 1/20 s. With $t_0$ the longest exposure you could hold unaided and $n$ the number of stops, the longest you can hold with help is

$$t_n = t_0 \times 2^{n}$$

Fractions work the same way, so 5.5 stops is a factor of $2^{5.5} \approx 45.3$. Run backwards, the stops between two times are $n = \log_2 (t / t_0)$, where $\log_2$ asks "two raised to what power gives this?" The kingfisher's gap, 1/600 s against 1/60 s, is a factor of ten, and $\log_2 10 \approx 3.32$ stops.

What Nikon Rates

The Reference Guide's specifications describe the mechanism and print no figure in stops. They list five-axis image sensor shift in the camera, and lens shift in lenses that have VR (p. 1002). The same chapter says that, unless stated otherwise, its measurements follow the standards of CIPA, the Camera and Imaging Products Association, the camera industry body that publishes standard test methods (p. 1009).

The figure in stops comes from Nikon's announcement of the camera on 17 June 2024, listed in the sources, which gives VR equivalent to 8.0 stops. A footnote sets the conditions: the figure is as of that date, follows CIPA standards, and was obtained at the telephoto end of the NIKKOR Z 24-120mm f/4 S with vibration reduction in NORMAL mode.

For a feel of the size, and only that: eight stops multiplies the usable time by $2^8 = 256$. From the rule's 1/120 s at that lens's 120 mm end, an illustrative starting point Nikon does not state, that is $256 / 120 \approx 2.1$ s. Read it as arithmetic about a standard test, not a forecast for a tired arm on a gusty day.

The 180-600 has a rating of its own. Nikon's announcement of the lens on 21 June 2023 gives its VR as equivalent to 5.5 stops, based on CIPA standards, at the longest focal length on a full-frame camera with the camera's VR set to NORMAL. As arithmetic, $2^{5.5} \approx 45.3$, and $600 / 45.3 \approx 13.3$, so from the rule's 1/600 s to about 1/13 s. Do not add the two ratings. I found no combined figure from Nikon for the Z6III with the 180-600, so I use none.

What VR Cannot Do

Stabilisation cancels the movement of the camera, not movement in front of it. A heron that turns its head during a 1/20 s exposure is blurred however steady the sensor is, and so is a dancer's hand mid-turn. The time subject movement allows is a separate question from the time shake allows, and the shorter answer wins. VR earns its keep on still subjects in poor light.

03.Two Places to Steady the Picture

Moving the Sensor

The Z6III's own stabiliser, camera on-board VR in the specifications, moves the image sensor (p. 1002). In general terms, a sensor-shift system senses how the body is turning and moves the sensor the opposite way, so the image stays put on it during the exposure. The specifications say five axes without naming them. Across the industry the phrase usually means tilting (pitch), turning (yaw), rotating around the lens axis (roll), and sliding sideways and vertically, and that reading of Nikon's five is mine.

Moving the sensor helps any lens in front of it, including one with no stabiliser of its own. It even reaches manual lenses that pass no information to the camera, once you enter their focal length and maximum aperture under Non-CPU lens data in the setup menu, which Nikon says gives them on-board vibration reduction (p. 826).

Moving Glass in the Lens

A VR lens such as the 180-600 carries its own stabiliser, a group of elements that shifts sideways to steer the image back into place, which the specifications call lens shift (p. 1002). At 600 mm a small tilt throws the image a long way, perhaps further than a sensor can travel on its mounting, and an element inside the lens can correct the image before it reaches the sensor, tuned to that one design. That is general reasoning about optics, not Nikon's account of how its two systems share the work.

How the Z6III Uses Both

Nikon documents only this much about the combination.

• The options under Vibration reduction vary with the lens attached (p. 498).
• With a Z mount lens that has built-in VR, Link VR to focus point tunes for the frame's centre even at ON (p. 499), and Nikon's camera announcement limits focus-point VR to NIKKOR Z lenses without VR.
• The 180-600's 5.5-stop figure was measured with the camera's VR set to NORMAL, according to Nikon's lens announcement.

How body and lens divide the correction, which axes each takes, and whether their effects add, is documented neither in the Reference Guide nor in the announcements I used. I do not guess. With the 180-600 attached, I plan around the lens's own rating.

Third-Party Lenses

My stage lens is the Tamron 70-180mm f/2.8 Di III VC VXD G2 for the Z mount. VC, short for Vibration Compensation, is Tamron's name for its optical stabiliser. Tamron's specification page for this lens, model A065, lists VC as present, but gives no figure in stops, no VC modes, and nothing on how VC works with a Nikon body's stabiliser. Nikon's Reference Guide does not mention third-party lenses on its VR pages.

So whether Vibration reduction offers the same choices with the Tamron is undocumented. To see them, attach the lens and open the menu, since the options vary with the lens (p. 498). The rest I judge from my own pictures, not from a number nobody has published.

04.The Vibration Reduction Menus

Vibration Reduction for Photos

The options for Vibration reduction are Normal, Sport and Off, though which appear depends on the lens (p. 498). The default is Normal (p. 447).

Nikon aims Normal at subjects that hold still and calls its correction enhanced. Sport is for subjects that move quickly and unpredictably, athletes being Nikon's example, and Off disables the system (p. 498). Nikon does not explain what differs inside. One clue sits on the same page: with Normal and a lens that supports VR, the viewfinder image may jiggle before the shutter fires, which Nikon presents as expected rather than a fault, offering Sport or Off if it distracts you (p. 498). My inference is that Sport trades some strength for a calmer view while you follow action.

Panning, swinging the camera to follow a moving subject, gets specific advice. Nikon recommends Sport, and in both Normal and Sport the system corrects only movement that is not part of the swing, so a horizontal pan gets only its vertical shake corrected (p. 498). That is what you want, since the swing is deliberate.

On a tripod or monopod Nikon recommends Normal or Sport, but adds that Off can be better with some tripods in some conditions, and that the best setting varies by lens, so the lens's documentation is worth reading (p. 498). Nikon also advises letting the image in the display settle before shooting (p. 498): raise the camera, wait a beat for the drift to stop, then press.

Pixel shift shooting, covered in the pixel shift part of this guide, cannot be combined with vibration reduction (p. 558). Vibration reduction is a default entry in the photo i menu, the quick-settings menu under the i button (pp. 83, 625), and the shooting display shows a VR indicator on both the monitor and the viewfinder (pp. 55, 61).

Vibration Reduction for Video

The video recording menu has its own Vibration reduction item, but by default it holds no value of its own. Its default is Same as photo settings (p. 579), which uses whatever the photo item is set to (p. 608), so changing the photo item to Sport changes video too. The video page names only that option and points back to the photo page (p. 608). I expect the other choices to be the photo ones, since the item drives the same hardware, but that is my reading. The item also sits in the default video i menu (pp. 84, 627), and Nikon warns that camera sounds during vibration reduction may be audible in footage (p. 109).

Video also has a separate stabiliser, Electronic VR. Rather than moving hardware, it records a smaller part of the frame and shifts that window to cancel shake. It is OFF by default (p. 579), turning it on makes the video crop smaller (p. 211), and Nikon's camera announcement puts the view at roughly that of a lens 1.25 times longer. That makes the recorded window about $1/1.25 = 0.8$ of the width, or $0.8^2 = 0.64$ of the area. Both video items belong to the video part of this guide.

Link VR to Focus Point

Why would the best correction depend on where you look? Consider roll, the camera rotating around the lens axis. Rotation turns the picture about its centre like a wheel on its hub: the hub stays put and the rim moves most. Suppose, purely as an illustration, a correction leaves a leftover roll of 0.0005 radians during an exposure. At the centre the image does not move. A corner of the FX frame is offset from the centre by half the sensor's 35.9 mm width across and half its 23.9 mm height up (p. 997), so by Pythagoras its distance is

$$\sqrt{17.95^2 + 11.95^2} \approx 21.6 \text{ mm}$$

The corner moves $21.6 \times 0.0005 \approx 0.011$ mm, about $0.011 / 0.00594 \approx 1.8$ pixels. How far a point moves depends on where it sits, so a correction tuned for one spot cannot be equally good everywhere.

Link VR to focus point picks the spot. ON tunes vibration reduction for the current focus point, and OFF for the centre of the frame (p. 499). The default is ON (p. 447). It uses whichever focus point is active when the shutter is released, and its effect cannot be previewed in the shooting display (p. 499). Nikon does not describe its method, so the roll example is my illustration of why position matters, not Nikon's mechanism.

Even at ON, the camera tunes for the centre in three cases (p. 499): with a Z mount lens that has built-in VR, when Auto-area AF (AF is autofocus) is the AF-area mode and several focus points are displayed, and while video is recording. Nikon's announcement is narrower: focus-point VR works only for photos, only with NIKKOR Z lenses that have no VR, and not while several focus points show. On its wording that also leaves out adapted and third-party lenses.

With the 180-600, a VR lens, the setting changes nothing. With a NIKKOR Z lens without VR, such as my 85mm f/1.8 S, which Nikon's lens page lists without VR, it moves the best correction to wherever I put the focus point. For the Tamron, a Z mount lens with its own stabiliser and not a NIKKOR, both of Nikon's statements suggest the centre is used, but Nikon names no third-party lenses, so that is my reading. I leave the item at ON: when it cannot act it costs nothing, and when it can it favours the part of the picture I chose.

05.Recommended Settings

Birds with the 180-600. Normal for a perched bird, because it is still and the stabiliser gives me the best chance at a slower speed and a lower ISO. When it flies, I switch to Sport through the i menu, if the menu offers it with this lens, since the options vary with the lens (p. 498). A flying bird needs a fast speed to freeze its wings anyway, so shake matters less, and the jiggle Normal can cause in the viewfinder is the last thing I want while following it.

Panning. Sport, as Nikon recommends, with the shutter speed chosen for the background streak I want.

Stage dance with the Tamron. Sport, if the menu offers it with that lens, since dancers move fast and without warning, which is how Nikon describes a Sport subject. Stage light pushes speeds down, but there the dancer's movement, not my hands, sets the slowest usable speed, and no stabiliser helps with that.

Portraits with the 85mm f/1.8 S. Normal, with Link VR to focus point at ON. The sitter is still, and with a single focus point on an eye near the edge of the frame, the correction can favour that eye.

Tripod. Nikon allows Normal or Sport on a tripod but says Off suits some tripods better (p. 498), without saying which. So I make one frame with VR on and one with it off at the speed I am using, compare them at 100 per cent, and keep the sharper setting for that tripod and lens.

Shutter type. Leave Custom Setting d6 Shutter type at its default, Auto (p. 624), which uses the electronic front-curtain shutter at slow speeds, where Nikon says it cuts the blur that camera shake causes (p. 668). I read that shake as the shutter's own jolt, which Shutter Types, Rolling Shutter and Flicker explains.

Video. I leave the video item at Same as photo settings so my stills choice carries over.

06.Beginner Mistakes

Expecting VR to freeze a moving subject. Stabilisation steadies the camera, not the bird or the dancer. Set the shutter speed for the subject's movement first, and let VR help only with yours.

Pressing the shutter before the picture settles. Nikon advises waiting for the display image to stabilise (p. 498). Raise the camera, pause, then press.

Leaving Normal on for pans. Nikon recommends Sport for panning (p. 498). Switch before the cyclist or the bird comes past.

Assuming Link VR to focus point works with every lens. With a Z mount lens that has its own VR, such as the 180-600, it falls back to the centre even at ON (p. 499).

07.Related Chapters

• Shutter Types, Rolling Shutter and Flicker: which shutter to choose, and the shutter's own jolt.
• Silent Shooting, Timers and Time-Lapse: the self-timer and other timed ways of firing the shutter.
• ISO and Auto ISO: the Minimum shutter speed setting that follows focal length.
• Image Area and Crop: the DX crop and equivalent focal length.
• Glossary: VR, stops, FX and DX in brief.