Image stabilization (IS) is a family of techniques to increase the stability of an image. It is used in image-stabilized binoculars, photography, videography, and astronomical telescopes. Image-stabilized binoculars are Binoculars that have a mechanism for decreasing the apparent motion of the view due to binocular movement Photography (fә'tɒgrәfi or fә'tɑːgrәfi (from Greek φωτο and γραφία is the process and Art of recording pictures by means of capturing Videography refers to the process of capturing moving Images on Electronic media (e Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study With still cameras, camera shake is particularly problematic at slow shutter speeds or with long focal length (telephoto) lenses. A Still camera is a type of Camera used to take Photographs Traditional cameras capture light onto Photographic film. In Photography, shutter speed is the length of time a shutter is With video cameras, camera shake causes visible frame-to-frame jitter in the recorded video. A video camera is a Camera used for electronic Motion picture acquisition initially developed by the Television industry but now common in other applications In astronomy, the problems of lens-shake are compounded by variations in the atmosphere over time, which cause the apparent position of objects to move.

Application in still photography

In photography, image stabilization can often permit the use of shutter speeds 3–4 stops slower (exposures 8–16 times longer), although even slower effective speeds have been reported.

The rule of thumb to determine the slowest shutter speed possible for hand-holding without noticeable blur due to camera shake is to take the reciprocal of the effective focal length of the lens. A rule of thumb is a principle with broad application that is not intended to be strictly accurate or reliable for every situation For example, at a focal length of 125 mm, vibration or camera shake would affect sharpness if the shutter speed was slower than 1/125 second. As a result of the 3–4 stops slower shutter speeds allowed by IS, an image taken at 1/125 second speed with an ordinary lens could be taken at 1/15 or 1/8 second with an IS-equipped lens and produce almost the same quality. The sharpness obtainable at a given speed can increase dramatically. ^[1] When calculating the effective focal length, it is important to take into account the image format a camera uses. For example, many digital SLR cameras use an APS-C image sensor that multiplies the effective focal length of the lens by 1. Advanced Photo System type-C ( APS-C) is an Image sensor format approximately equivalent in size to the Advanced Photo System "classic" size negatives 5 or 1. 6, depending on the camera. This value is referred to as the crop factor, field-of-view crop factor, focal-length multiplier, or format factor. In Digital photography, a crop factor is the ratio of the dimensions of a camera's imaging area compared to a reference format most often this term is applied to

However, image stabilization does not prevent motion blur caused by the movement of the subject or by extreme movements of the camera. Motion blur is the apparent streaking of rapidly moving objects in a still image or a sequence of images such as a movie or Animation. Image stabilization is only designed for and capable of reducing blur that results from normal, minute shaking of a lens due to hand-held shooting. Some lenses include a secondary panning mode or a more aggressive 'active mode', both described in greater detail below under optical image stabilization. Panning refers to the horizontal movement or rotation of a film or video camera or the scanning of a subject horizontally on video or a display device

Techniques of image stabilization

Optical Image Stabilization

An image comparing two close-up photographs of a keypad. The top image does not have Optical Image Stabilization enabled, the bottom image does.

An Optical Image Stabilizer, often abbreviated as OIS or OS, is a mechanism used in a digital still camera or video camera that stabilizes the recorded image by varying the optical path to the sensor. ^[2] This technology is implemented in the lens itself rather than in the camera, as are other techniques described below. The primary reason for this to avoid building glass lenses into the camera body which would increase its size dramatically, and placing the IS inside the lens allows for the system to be fine-tuned for the characteristics of that particular lens. Different companies have different names for the OIS technology; for example: Image Stabilization (IS - Canon, the first to produce an OIS lens), Vibration Reduction (VR - Nikon), MegaOIS (Panasonic and Leica), Super Steady Shot (SSS - Sony), Optical Stabilization (OS - Sigma), Vibration Compensation (VC - Tamron) and Shake Reduction (SR - Pentax). is a Japanese Multinational corporation that specializes in imaging and optical products including Cameras photocopiers and Computer printers ( also known as Nikon or Nikon Corp, is a Multinational corporation headquartered in Tokyo Japan specializing in Optics is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with ( is a Japanese company manufacturing Photographic lenses optical components and commercial/industrial-use optics is a wholly owned division and brand name of Hoya Corporation.

In Nikon and Canon's implementation, it works by using a floating lens element that is moved orthogonally to the optical axis of the lens using electromagnets. The EF lens mount allows all the Canon EF lenses to be used on any of the Canon EOS line of Cameras made by Canon Inc A photographic lens (also known as objective lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with Vibration is detected using two piezoelectric angular velocity sensors (often called gyroscopic sensors), one to detect horizontal movement and the other to detect vertical movement. Do not confuse with Angular frequency The unit for angular velocity is rad/s A gyroscope is a device for measuring or maintaining orientation, based on the principles of Angular momentum. ^[3] As a result, this kind of image stabilizer only corrects for pitch and yaw axis rotations,^[4] and cannot correct for rotation around the optical axis. Some lenses have a secondary mode that counteracts vertical camera shake only. This mode is useful when using a panning technique, and switching into this mode depends on the lens; sometimes it is done by using a switch on the lens and on others it is automatic. Panning refers to the horizontal movement or rotation of a film or video camera or the scanning of a subject horizontally on video or a display device

Some of Nikon's more recent VR-enabled lenses offer an 'Active Mode' that is intended to be used when shooting from a moving vehicle, such as a car or boat, and should correct for larger shakes than the 'Normal Mode'. ^[5] However, Active Mode, when used under normal shooting conditions, can result in poorer results than the 'Normal Mode'. ^[6]

Most manufacturers suggest that the IS feature of a lens be turned off when the lens is mounted on a tripod as it can cause erratic results and is generally unnecessary. Many modern image stabilization lenses (notably Canon's more recent IS lenses) are able to auto-detect that they are tripod-mounted (as a result of extremely low vibration readings) and disable IS automatically to prevent this and any consequent image quality reduction. ^[7] The system also draws power from the battery, so de-activating it when it is not needed will extend the time before a recharge is required.

Image stabilization is also effective in reducing blur resulting from mirror-slap in newer versions of IS only; mirror lockup can be utilized to compensate instead when using an older IS system or none at all. Mirror lock-up (often abbreviated to MLU) is a feature employed in many Single Lens Reflex (SLR cameras today to reduce vibration (causing Motion

Moving the image sensor

The sensor capturing the image can be moved in such a way as to counteract the motion of the camera, a technology often referred to as mechanical image stabilization. When the camera rotates, causing angular error, gyroscopes encode information to the actuator that moves the sensor ^[8]. The sensor is moved to maintain the projection of the image onto the image plane, which is a function of the focal length of the lens being used; modern cameras can acquire focal length information from the lens mounted. Konica Minolta used a technique called "anti-shake" now marketed as SteadyShot in the Sony α line and "shake reduction - SR" in the K10D and K100D lines by Pentax, which relies on a very precise angle speed sensor to detect camera motion. is a Japanese manufacturer of office equipment Medical imaging, Graphic imaging, Optical devices and Measuring instruments The company SteadyShot is the trademarked name of an integrated Video camera Image stabilisation technology developed by Sony for its range of Consumer and Sony α ( Greek letter alpha) is a Digital SLR camera system introduced on June 5, 2006. ^[9] Olympus introduced image stabilization with their E-510 D-SLR body, employing a system built around their Supersonic Wave Drive. ( is a Japanese company specializing in Optics and Imaging. Olympus was established on October 12 1919 initially specialized in microscope The Olympus E-510 (or Olympus EVOLT E-510 in North America) is a 10 megapixel digital single-lens reflex (DSLR camera oriented to the "prosumer" A digital single-lens reflex camera ( digital SLR or DSLR) is a Digital camera that uses an automatic mirror system and Pentaprism ^[10] Other manufacturers use DSPs to analyze the image on the fly and then move the sensor appropriately. A digital signal processor ( DSP or DSP micro) is a specialized Microprocessor designed specifically for Digital signal processing, generally Sensor shifting is also used in some cameras by Fujifilm, Pentax, Samsung, Casio Exilim and Ricoh Caplio^[11].

The advantage with moving the image sensor, instead of the lens, is that the image will be automatically stabilized regardless of what lens you are using. This means that buying another lens for your camera is cheaper, and the lenses weigh less.

One of the primary disadvantages of moving the image sensor itself is that the image projected to the viewfinder is not stabilized. However, this is not an issue on cameras that use an electronic viewfinder (EVF), since the image projected on that viewfinder is taken from the image sensor itself. An electronic viewfinder or EVF is a Viewfinder where the image captured by the lens is projected electronically onto a miniature display

Digital image stabilization

Digital image stabilization is used in some video cameras. This technique shifts the electronic image from frame to frame of video, enough to counteract the motion. It uses pixels outside the border of the visible frame to provide a buffer for the motion.

Stabilization filters

Many non-linear editing systems use stabilization filters that can correct a non-stabilized image by tracking the movement of pixels in the image and correcting the image by moving the frame. "NLE" redirects here For the standardized test see National Latin Examination. A filter is a computer program to process a Data stream. Some Operating systems such as Unix are rich with filter programs The process is similar to digital image stabilization but since there is no "larger" image to work with the filter either crops the image down to hide the motion of the frame or attempts to recreate the lost image at the edge through extrapolation. In Mathematics, extrapolation is the process of constructing new data points outside a Discrete set of known data points

Orthogonal Transfer CCD

Used in astronomy, an orthogonal transfer CCD (OTCCD) actually shifts the image within the CCD itself while the image is being captured, based on analysis of the apparent motion of bright stars. A charge-coupled device ( CCD) is an analog Shift register, that enables the transportation of analog signals (electric charges through successive stages (capacitors This is a rare example of digital stabilization for still pictures. An example of this is in the upcoming gigapixel telescope Pan-STARRS being constructed in Hawaii. Pan-STARRS (an Acronym for Panoramic Survey Telescope And Rapid Response System is a planned astronomical survey that will conduct Astrometry and Photometry ^[12]

Stabilizing the camera body

A technique that requires no additional capabilities of any camera body–lens combination consists of stabilizing the entire camera body externally rather than using an internal method. This is achieved by attaching a gyroscope to the camera body, usually utilizing the camera's built-in tripod mount. A gyroscope is a device for measuring or maintaining orientation, based on the principles of Angular momentum. This allows for the external gyro to stabilize the camera, and is typically employed in photography from a moving vehicle, when a lens or camera offering another type of image stabilization is not available. ^[13]

References

1. ^ Ken Rockwell, "Why IS and VR Matter"
2. ^ What is Optical Image Stabilizer?, Technology FAQ, Canon Broadcast Equipment
3. ^ Glossary : Optical : Image Stabilization, Vincent Bockaert, Digital Photography Review
4. ^ Panasonic Mega OIS Explained
5. ^ Vibration Reduction (VR) Technology
6. ^ CameraHobby: Nikon AF-S VR 70-200mm f2.8 Review
7. ^ Canon IS vs. Nikon VR
8. ^ [1], Development of a Test Method for Image Stabilization Systems
9. ^ Dynax 7D Anti-Shake Technology, Konica Minolta
10. ^ Olympus Image Stabilization Technology
11. ^ http://www.outdoorphotographer.com/content/2007/mar/image-stabilization3.shtml
12. ^ Pan-STARRS Orthogonal Transfer CCD Camera Design, Gareth Wynn-Williams, Institute for Astronomy
13. ^ Multimedia: Use Image Stabilization, Andy King, Web Site Optimization, 2004

See also

• Adaptive optics
• Heligimbal