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29 May 2009
Due to the many technological advancements in recent times, modern photography is becoming more and more a case of point and shoot. One of the main features included in today's compact digital camera, which makes photography so simple, is the image stabilisation system.
The image stabilisation (IS) system is a collection of clever processing and mechanical techniques to improve the stability of the images we take, especially useful at reducing the effects of camera shake at slow shutter speeds.
There are various different ways to achieve a stabilised image, including optical image stabilisation, digital image stabilisation and also by moving the image sensor. Each technique has its advantages and disadvantages.
Optical image stabilisation (OIS) is located in the lens itself rather than the camera, and achieves stability by varying the optical path to the sensor.
In a digital camera such as the Panasonic Lumix DMC TZ6 the MEGA OIS system (as Panasonic like to call it) uses gyrosensors to detect camera shake, then shift the lens to compensate.
Many manufacturers recommend disabling the image stabiliser when the camera is tri-pod mounted, as the technology is not really necessary, and can just use extra battery power.
Digital image stabilisation is perhaps more reliable as there are no moving parts and everything is done electronically. The technique shifts the electronic image enough to counteract the hand-shake. Often pixels are used outside the border of the visible frame, to provide a buffer for the motion.
Finally, mechanical image stabilisation (actually moving the sensor which captures the image) can be used to stabilise the picture. As the camera rotates, gyroscopes send angular information to the actuator, which in turn moves the sensor to compensate.
One of the advantages of MIS (moving the sensor) over OIS (moving the lens), is that the image will be stabilised regardless of what lens is being used. Lenses should generally be cheaper and weigh less for an MIS camera.
So which technique is the best? Well there is no easy answer, as each has its advantages and disadvantages, and technology varies between the different manufacturers. But generally, optical image stabilisation can give better results, whereas digital image stabilisation may be more reliable (due to a simpler system with no moving parts).
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