if you are a photographer and you like to take pictures with your smartphone, you must have the best camera around to take the most shinny and clear shots. So, when going through the specs you may hear a lot of photography specific terminology but the one that you may consider to have it in your camera is the optical image stabilization. So, what is exactly Optical image stabilization and why it is so important?
Electronic vs Optical Image Stabilization
There is a great bit of distinction between electronic and optical image stabilization. Don’t be fooled by tall claims by camera and smartphone makers when they promise you digital image stabilization. Optical image stabilization (OIS) is the clear winner. It involves actually physically moving the lens or the sensor—depending on the type of stabilization system—and corrects the image coming through the lens to ensure that it is perfectly aligned with the sensor.
What is Image stabilization?
Image Stabilization (or IS) is a method to reduce the likelihood of taking blurry photos by moving the camera lens automatically to compensate for camera movement which can be induced by the user hand-holding the camera, or because the camera is fixed on a platform prone to vibration or movements, like vehicles, helmets etc.
Optical Image Stabilization (or OIS) is a term that gets thrown around a lot these days given that many people expect flagship smartphones to have this feature. It’s evident from the term itself that this feature has something to do with the camera, and the fact is that OIS plays a vital part in ensuring great digital reproduction in a still image or recorded video.
OIS eliminates a very common problem: blurry photos induced by user movements (shaking, screen tap), or motion of the camera in general (maybe you’re mounting the camera on a bike/helmet).
Ultimately, camera movement may result in blurry pictures and video, which is not only frustrating, but also brings up the need to capture that picture or video once again to ensure that there’s no blur. OIS certainly goes a long way in making our lives easier, as illustrated by the photo posted below.
Obviously it won’t help if the device is being violently shaken, and even OIS can only help eliminate blur up to a certain limit (because the lens module can be moved only by so much inside the camera), but it’s vital to understand that this feature goes a long way in compensating for normal usage unwanted camera motion. It should also be kept in mind that Optical Image Stabilization does not do anything to prevent motion blur, which is also caused by subjects moving around fast.
Electronic Image stabilization
As opposed to EIS which uses complex algorithms for improving image quality, Optical Image Stabilization is a purely mechanical solution. The required result is achieved by adjusting the optical path to the image sensor, by moving or tilting the lens module to compensate or counteract user movement. Lens shift and module tilt are two methods which are widely used, position of the lens moves in the former whereas the entire module itself moves in the latter to stabilize the target image.
Blur seen in photos and videos is caused by the movement of optical path between focusing lens and the image sensor’s center. In the lens shift method only the lens inside the camera module is capable of making very small shifts in optical elements so that the change in optical path can be countered. In the other method the entire module, which includes the image sensor and the fixed lens, has controlled movement to achieve image stabilization.
To correct movement OIS relies upon various sensors which characterize the movement in the X/Y-plane. Different sensors also detect pitch/tilt and yaw/pan movements. All collected data is then used to measure how much re-positioning is needed in the lens position to ensure that the optical path is precisely center to the image sensor.
EIS may achieve similar results but it comes as cost to image quality (like cropping out parts of the original image, thus reducing the field of view). OIS reduces image blur without having to compromise on image quality. Note that it is possible to use both OIS and EIS techniques at the same time. The advantage for EIS is that it relies only on software, while OIS needs additional camera hardware. Optical Image Stabilization tends to be more expensive.
Image stabilization technologies are not new. Professional still and video cameras have had stabilization technologies for a long time, but OIS is particularly gaining popularity because camera and camera module makers have been very good at reducing the footprint of the stabilization system to ever smaller form-factors, that are even compatible with phones.