Image stabilization

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Use of the AntiShake system instead of the flash in the Miniatur Wunderland Hamburg, the windows show the settings of the camera ( 1 ⁄ 10  s at 104 mm focal length)

In photo technology, image stabilization is a process used to avoid blurring .

background

According to a rule of thumb, the so-called free hand limit for photographing in 35mm format is the reciprocal of the focal length of the lens used; With a steady hand, a 200 mm telephoto lens can therefore take shake-free pictures from a shutter speed of 1/200 second; however, this rule of thumb only applies to a limited extent for super telephoto lenses . In addition to a blur-free image, an image-stabilized telephoto lens has the advantage that the viewfinder image is stable. This is a gain in convenience for the user.

According to the manufacturer, the practical gain of image stabilization is up to four and a half f-stops , which means that it enables up to twenty-two times the exposure time compared to the non-stabilized system. Therefore, an image stabilizer expands the possibilities of freehand photography in terms of shutter speed and the focal length of the lens. However, it is assumed that the motifs are still. Only a shorter exposure time helps against motion blur . In sports and concert photography, for example, the benefits of image stabilization are often less than hoped for or no longer exist at all.

Operating principles

Different, also combinable methods of image stabilization

A distinction is made between various methods of image stabilization, each of which is offered by the photo industry under proprietary names .

Mechanical image stabilization

Mechanical image stabilization can be carried out by propping up the camera, using a tripod or a gyro stabilizer . Steadicam systems are used to mechanically stabilize a handheld camera or Cineflex cameras to stabilize aerial photos, especially when recording moving images .

Optomechanical image stabilization

The image stabilization mechanism can either be located in the lens or by the image sensor . Image stabilization lenses are offered by Canon , Nikon , Sigma , Tamron , Sony , Leica , Panasonic and Fujifilm , while Konica Minolta , Pentax , Olympus , Sony, Fujifilm and Panasonic offer sensor-based image stabilization . With optical image stabilization, either the image circle above the image sensor (when implemented in the lens) or the image sensor below the image circle (when implemented in the housing) is shifted.

One advantage of image stabilization on the image sensor is that the mechanism can basically benefit all available lenses and does not need to be implemented in every lens. However, with SLR cameras only the stabilizers integrated into the lens offer the possibility of seeing a stabilized image when looking through the viewfinder. With digital compact cameras and mirrorless system cameras, stabilized images can be displayed both in the electronic viewfinder and on the monitor while searching for a subject. Stabilized interchangeable lenses can also be used on analog SLR cameras.

The movement of the optical devices is detected with the help of acceleration sensors. For a particularly extensive image stabilization, the acceleration caused by the rotation of the earth around its axis and around the sun must also be taken into account and eliminated to compensate for the movement in relation to the earth's surface . This also applies if the camera and the object to be photographed do not move at all relative to each other, as the direction of this system changes permanently in relation to an inertial system and thus acceleration forces are generated, although this does not seem to change the position of the system at all for an observer on the earth's surface cause. If the camera moves in relation to the earth's surface, the Coriolis force may also have to be included. Without taking these effects into account, up to six and a half f-stops can be achieved in practice by extending the possible blur-free exposure time . In this case, the exposure can be approximately 90 times longer with image stabilization than without image stabilization, if you want to take blur-free pictures.

Implementation in the lens

Here are the stabilizing elements - prisms , lenses or other optical elements - in the lens of the camera; one or more optical elements are movable and can be controlled horizontally and vertically on the basis of measurements from two or three sensors. One of the sensors determines the horizontal movement, the other the vertical movement and the third the position of the compensation element. Because optical elements are shifted, this implementation is always associated with a (slight) loss of quality. Chromatic aberration can occur to a greater extent , especially in the edge areas .

Proprietary image stabilization systems
  • Image Stabilizer (IS)
    • Canon :
      It is built into photo and video lenses as well as binoculars. There are up to four different operating modes depending on the lens: a) Correction in horizontal and vertical direction, b) Correction only in horizontal direction, c) Correction only in vertical direction, d) switched off. Modes b and c are particularly suitable for photos of fast moving objects ( dragging ).
    • Olympus :
      Since 2016,       Olympus has also been using the term “IS” for lenses with integrated image stabilizers, which in Sync-IS mode can be synchronized with the image stabilizer in the Micro Four Thirds camera housing in order to be able to achieve even greater protection against shake.
  • Optical Image Stabilizer (OIS)
    • Panasonic :
      With the       Panasonic optical image stabilizer (OIS), a small lens in the lens is moved horizontally by two linear motors; the motors are controlled by two gyro sensors (horizontal and vertical). Vibrations of around 1 to 10 Hz are compensated.
      More recent Panasonic cameras have two stabilizer modes: Always active (mode 1) and only active when the shutter button is pressed halfway (mode 2). In the second case, not only is electricity saved, but the movable lenses do not hit a stop as quickly because they are held in the middle when inactive. This allows the tremor to be compensated more reliably. In mode 1, on the other hand, it can happen that the lens reaches the edge of the horizontal or vertical movement area when the camera moves more strongly. But the viewfinder image is quieter. In the dual IS mode introduced in 2015 , it is possible to synchronize the image stabilizers of lenses and camera housings in order to achieve a stronger compensation effect.
    • Fujifilm : The supplier Fujifilm also uses the letter combination OIS to identify lenses with a built-in image stabilizer.
  • Optical Stabilizer (OS), Sigma .
  • Optical SteadyShot (OSS), Sony .
  • Vibration Compensation (VC), Tamron .
  • Vibration Reduction (VR), Nikon .

Implementation in the camera housing

The image stabilization in the camera housing works in principle in the same way as the optical image stabilization in the lens, except that no optical compensation elements are moved, but the image sensor directly . In principle, all existing interchangeable lenses for image stabilization are compatible with a single-lens reflex camera housing with built-in image stabilization, so the entire range of lenses does not need to be exchanged, and lenses from third-party manufacturers such as Tamron or Sigma can also be used. Panasonic has been using the Dual IS process to synchronize the image stabilizers of its lenses with the image stabilizers integrated in the camera housing since 2015 . This process has also been offered by Olympus since 2016 under the name "Sync IS" .

Proprietary image stabilization systems

  • Image Stabilization (IS) from Olympus
  • Shake Reduction System (SR) from Pentax
    At the moment of triggering, the sensor is moved electromagnetically so that the image on the sensor is still. As the first image stabilization system, it can not only compensate for horizontal and vertical movements, but also rotation around the image axis. The maximum possible stroke of the sensor along the image plane is two to three millimeters.
    The system was first used in 2006 in the Pentax Optio A10 compact cameraand then in the     K100D and K10D digital SLR cameras . For the K10D, Pentax specifies an effectiveness of the "Shake Reduction" of up to four light values. This means that in the best case, an exposure time that is 16 times longer can be kept blur-free than without stabilization. The information about the focal length required for the stabilization function is automatically communicated to the camera by newer lenses. If this is not the case, the focal length value can be entered via the camera menu. In this way, old or adapted lenses can also be used with stabilized shake reduction on cameras.
  • SteadyShot Inside (SSI) bySony, based on the Super SteadyShot system from Sony, was originally called Anti Shake (AS) fromMinoltadeveloped. While only two axes have been stabilized so far, Sony introduced a five-axis image stabilizer in 2014 with the full-frame camera ILCE-7M2, which, depending on the situation, should be able to catch up to 4.5 exposure levels.
  • Super Steady Shot (SSS) bySony, was originally developed as AntiShake (AS) byMinolta.
  • Vibration Correction from Ricoh

Electronic image stabilization

Electronic image stabilization is mainly used in video cameras . But there are also implementations in cameras that are mostly based on sharpening the images or on an automatic increase in the sensitivity of the sensor.

  • electronic Vibration Reduction (e-VR) from Nikon , Coolpix S4
  • Anti Shake DSP in some Exilim models from Casio
  • Advanced Shake Reduction (ASR) from Samsung. The ASR function combines an underexposed picture with a short shutter speed and a correctly exposed picture with a correspondingly long shutter speed. The sharp, underexposed version is brightened with the color information of the blurred image.

Some manufacturers refer to the automatic increase in the exposure index in poor lighting conditions as digital image stabilization (e.g. anti-shake DSP ). This enables shorter exposure times, which is why the images are less blurred. The increased sensor sensitivity, however, leads to poorer image quality due to increased image noise or the necessary de-noise. The increase in sensor sensitivity is often possible even with cameras that do not advertise this type of digital image stabilization. So this method is not a real image stabilization and is mostly only used for marketing.

Information technology image stabilization

Another problem than with individual images arises when taking series images or moving images, in which shaking effects arise between the individual images when using hands-free operation. Technically, this means that the photographed subject has apparently moved between successive individual images. Such effects can be compensated within limits if the video camera is able to measure the wobbling movements, consisting of linear accelerations and rotations, separately. These accelerations and rotation rates are measured by inertial sensors and recorded and corrected by a microprocessor. The captured image is corresponding to the (unwanted) movement excised and optionally interpolated again. As an undesirable side effect, however, an intentional slow panning of the camera can possibly result in an undesirable jerking.

Synthetic image stabilization

Alternatively, a motif analysis can also be carried out subsequently in the recorded images using software that determines the position of the recorded motifs and combines appropriate sections of the individual images to form a stabilized image sequence.

With the help of the “ Post Production Stabilizer ”, synthetic image stabilization is possible even after a film has been recorded. Such motion tracking software offers, for example:

History and Development

Nikon introduced the first camera with an image stabilization function in 1994 with the Zoom 700VR .

In 1995 Canon launched the first interchangeable lens for 35mm cameras with an optical image stabilizer with a 75–300 mm telephoto zoom .

The first image stabilizer integrated into the housing in a digital SLR camera was used in 2004 in the form of the AntiShake system in the Konica Minolta Dynax 7D . This solution represented a further development of the technical comparable systems that formerly in Minolta - Bridge cameras were used. The first full-frame camera with an image stabilizer (SteadyShot) integrated into the housing followed in 2008 with the Sony Alpha DSLR-A900 .

At the end of 2012, Nokia released the Lumia 920, the first smartphone with an optically stabilized image sensor. This year, with the Olympus OM-D E-M5, the first model with 5-axis image stabilization was presented, which can compensate for horizontal and vertical displacement and tilting as well as rotation in the case of image shake.

The first full-format camera housing with an image sensor stabilized in five axes was the mirrorless model alpha 7 II from Sony at the end of 2014 . The camera housing can combine the image stabilization on the image sensor with that in a correspondingly equipped lens in order to increase the scope for compensation. Each axis is only stabilized by the system that is more suitable in each case.

Hands-free recording of a historical universal theodolite without flash and with synchronized image stabilizers of the image sensor and lens ("Dual IS"). The picture was taken with a Panasonic Lumix DMC-GX8 with a telephoto lens with a focal length of 42.5 millimeters at a f-number of 1.2 and a polarizing filter in order to eliminate the reflections on the front glass of the showcase (exposure index ISO 800, exposure time 1/8 second / equivalent for the small picture: 85 millimeter focal length, f-number 2.4, exposure index ISO 3200, exposure time 1/8 second).

With the Panasonic Lumix DMC-GX8 followed half a year later, the first model in the mirrorless Micro Four Thirds system with the possibility of full synchronization of image stabilizers of image sensor and lens (Dual IS).

Other uses

Since the early 2000s there have also been binoculars and binoculars with mechanical image stabilization, such as the Zeiss 20x60S , the Canon 15x50 IS or the Fujinon Techno-Stabi 14x40 .

Web links

Wikibooks: Digital imaging processes: Image acquisition # Image stabilization  - learning and teaching materials

Individual evidence

  1. ↑ Andy Westlake: Exclusive interview: Setsuya Kataoka of Olympus , Amateur Photographer, September 20, 2016, accessed June 12, 2017
  2. ↑ Two new OLYMPUS M.ZUIKO PRO lenses and one M.ZUIKO Premium Macro , olympus.com from September 19, 2016, accessed on June 12, 2017
  3. ↑ Panasonic Lumix GX8 With Dual IS Technology , ephotozine.com, July 16, 2015, accessed June 12, 2017
  4. ↑ European Photo Innovation 2016-2017 - Panasonic Dual IS System  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , eisa.eu 2016/2017, accessed on June 12, 2017@1@ 2Template: Dead Link / www.eisa.eu  
  5. ↑ Moritz Wanke: Optical image stabilizer: Sharp pictures from the hand , chip.de from May 29, 2015, accessed on June 12, 2017
  6. ↑ Steffen Herget: Tried: Nokia Lumia 920 in short hands-on ( German ) In: teltarif.de . teltarif.de . September 6, 2012. Retrieved September 9, 2014.
  7. ↑ Olympus presents mirrorless system camera , futurezone.at, February 8, 2012, accessed on March 1, 2016
  8. ↑ Sony presents the Alpha 7 II with integrated image stabilizer , dkamera.de, November 20, 2014, accessed on March 1, 2016
  9. ↑ Panasonic Lumix GX8: First MFT camera with 20 megapixels , fotomagazin.de, July 16, 2015, accessed on March 1, 2016
  10. ↑ Mark Vincent: A Review: IS Binos , June 2002, accessed October 24, 2019
  11. ↑ Jan Meijerink: De Fujinon 14x40 Techno-Stabi , Rijssen, September 2001, accessed on October 24, 2019