Optical Image Stabilization (OIS) Explained: Types and Working

Catalog

ⅠTypes of Image Stabilization

The effect of optical image stabilization is quite obvious. Normally, this function can improve the 2-3 gear shutter speed, so that the handset does not produce an ambiguous phenomenon, which is very obvious for beginners. In addition, in the telephoto type digital camera, optical image stabilization also works.

OIS is an anti-shake technology that is most recognized by the public, which is compensated by a movable part, thereby achieving an effect of alleviating photos blur. The optical image stabilization technique is divided into two major factions, namely the lens mobile optical image stabilization of the lens manufacturer, and CCD mobile optical image stabilization represented by emerging electronic vendors. However, since optical image stabilization needs to be implemented using additional components, it also leads to the high cost of optical image stabilization systems, and the model market selling the optical image stabilization system is still more expensive.

1.Lens-based image stabilization

Camera module with optical image stabilization (OIS)

Through the lens group, the image stabilization is mainly based on Canon and Nikon, which rely on magnetically packaged suspensions, thereby effectively overcoming image blur due to camera vibration, which is more obvious to the digital camera of the large zoom lens. Typically, the gyroscope inside the lens detects tiny movement and transmits the signal to the microprocessor immediately. The microprocessor calculates the displacement amount that needs to be compensated. Then the light path will pass through the compensation lens group. According to the shake direction and displacement of the lens, the compensation lens group will adjust the position and angle accordingly to keep the optical path stable, thereby efficiently overcoming the imaging blur of the camera shack.

2.CCD image stabilization

The image stabilization is achieved by CCD, which is the purpose of relying on the CCD to achieve anti-shake. The principle is to secure the CCD first on a bracket that can move up and down. Sensing the direction and amplitude of camera shake through the gyroscope, and then transmits these data to the processor for screening, enlarges. The processor finally calculates the amount of CCD movable to cancel the shack.

3.Electronic image stabilization

The so-called electronic image stabilization (EIS), that is, the whole process of image stabilization does not have any component assistance and participation, relying on digital processing technology to achieve image stabilization. The current electronic image stabilization mainly is achieved by two types of technologies. One is to increase camera sensitivity (ISO) and another is "digital image stabilization" achieved by pixel compensation or other operational methods.

4.Dual image stabilization

The so-called "double image stabilization" is a digital camera image stabilization system consisting of two technologies of "optical image stabilization" and "high sensitivity". Among them, optical image stabilization is a more complex technique, which relies on the camera's built-in precision gyroscope and a set of movable lenses to calculate and correct the light offset caused by the hand. The principle of “high sensitivity” is relatively simple, which is to improve the shutter speed by increasing the sensitivity ISO value, and can also achieve the image stabilization effect.

Ⅱ Working principle of Optical Image Stabilization

1.Lens-based optical image stabilization

The first optical image stabilization system for civilian cameras in the world is developed by Canon. EF 75-300mm F4-5.6 IS USM lens is the first application of an optical image stabilization system on a civilian camera. At the time, the industry was indeed shocked throughout the industry, and the visibility of the Canon EF autofocus lens gradually increased, which is called Canon's IS (Imagine Stabilizer) optical image stabilization system. It is mainly to compensate for the shake of the camera through the movement of the lens. In Canon's image stabilization lens, it is equipped with a gyro sensor. It can accurately detect the vibration of the hand and convert it into an electrical signal. After the built-in computer processing, control a set of modified optical components as a film or CCD. The plane is moving in parallel, offset the imaging light shift due to the hand shock. This system can effectively improve the effect of handheld shooting.

Optical image stabilization internal structure

The Canon IS lens can detect the shake of the camera through a pair of built-in gyroscope sensors, and adjust the lens assembly to the direction of jitter to cancel this jitter to prevent the picture from blurring. If the image stabilization function is enabled, the camera will start the camera jitter compensation after 0.5 seconds. The lens with IS can theoretically reduce the second to three-level shutter speeds. Since the potential optical performance of the lens is optimized, you can capture a beautiful image.

Optical image stabilization principle

In the past, IS lenses allowed you to use a shutter speed that was 2 levels lower than the theoretical shutter speed. As this technique is constantly developing, it is already possible to use shutter speeds 3 levels lower than the theoretical shutter. On the latest release of Canon EF 70-200mm f / 4l USM, Canon's latest generation IS optical image stabilization system is equipped, theoretically reduces the 4-speed shutter speed, which is the king of the image stabilization lens.

2.Sensor-shift optical image stabilization

Since the lens-based optical anti-shake is high in production technology and cost, some manufacturers developed the sensor-shift optical anti-shake (CCD anti-shake) system. This technique has occurred as the digital camera appears because its principle determines that the film machine cannot be imitated in this way.

The principle of sensor-shift optical image stabilization is much simpler than Lens-based optical image stabilization. That is to fix the photosensitive element (CCD / CMOS) of the digital camera on a platform that can slide through the electromagnetic effect. When shooting, the platform will use the hysteresis of the electromagnetic to fix the CCD in a short period of time, which is reached to some extent the purpose of anti-shake.

CCD optical image stabilization technology is first known as the AS (Anti Shake) system developed by Konica, and is first applied to its high-end consumption digital camera A1, and has received excellent market effects. Since then, Konica Beauty can transplant this technology to digital SLR α7 Digital and α5 Digital, and receive a warm welcome from the market. This technology is also mastered by Sony Machine in Konica Merco-up imaging. Due to the late development of this technology, the technology is not as mature as the lens anti-shake. But with the continuous introduction of new models of various brands, its image stabilization performance has also been steadily improved, and it has great momentum to catch up with the lens-based image stabilization. For example, Pentax’s newly released SLR digital camera K10D claims to be able to achieve level 3 anti-shake, which is a level higher than the level 2 anti-shake of its predecessor K100D.