Optical image stabilisation (OIS)
How optical image stabilization works
The principle is similar to mechanical stabilization , with the difference that the movement does not take place on the sensor but inside the lens. Therefore, the image coming to the sensor is already still, just like you see it in the viewfinder.
It is often necessary to set slower shutter speeds in low light conditions so that images are not too dark. However, this carries the risk of blurry images because the camera can not be kept completely still without a tripod. However, the Image Stabilizer compensates for the hand-shake so even at slow shutter speeds (e.g. 1/30) images are still sharp.
Advantages and disadvantages of optical stabilization
- There is no image degradation
- The stabilization result can be immediately seen in the viewfinder
- It can be used with all available resolutions
- The most important part of the camera (sensor) is mechanically fixed
- For interchangeable lens cameras, each lens must be optically stabilized
- It usually isn't built into wide-angle lenses
- Does not apply when shooting scene in motion
- High power consumption
Photo on the left was taken without lens stabilization. The image on the right taken with an optical stabilization lens.
When optical stabilization is effective
Optical stabilization can be used in all light conditions, but only when capturing a still scene. In that case, stabilization allows you to shoot at up to 3 times slower exposure than without stabilization.
When optical stabilization does not help
If we want to shoot a moving scene, stabilization doesn't have any effect. This is because the stabilizer moves the system inside the lens to balance the movement of the photographer's hands. A fast-moving scene is best captured with a fast shutter speed combined with a low aperture lens.
