If cameras are one of your top priority in a smartphone, then one of the first specs you gotta check on a smartphone is the image stabilization technology being offered. Theoretically, optical image stabilization (OIS) is said to be the best, but this ain’t the case if you’re shooting a lot of videos. as Electronic Image Stabilization (EIS) actually works better for video.
Yes, OIS takes the lead when it comes to still photos, but the same can’t be true for videos. Both stabilization systems help to reduce any shaking of the camera footage, but, EIS is a better choice for making videos.
How OIS Works?
OIS works on a smartphone by suspending lens over the camera module by using springs and electromagnets. The smartphone while recording a video detects the frequency and amplitude if there is any shaking, it then uses the electromagnets to coordinate the output and set the angle of the lens. The lens actually moves in the opposite direction of the shake, which allows the image to re-centre itself on the image sensor.
All this happens before the image pops into the image sensor, which shows that the image is not degraded. OIS uses a smartphone’s gyroscopic sensors to help in detecting shake. The gyro-sensors scale movements and forwards this data to a “micro centre,” which then moves the lens accordingly to offset the motion.
So OIS mechanically moves the image sensor in response to any shake or tremor detected on a smartphone while recording footage or capturing an image. The physical movement of the lens, obviously, takes some time, which becomes handy when you are shooting a video in high frame rate. A con of OIS is that movement of the lens with respect to the image sensor can sometimes lead to output with a warped perspective, which brings about a “jello effect” in videos you shoot.
How EIS Works
Electronic Image Stabilization, on the other hand, works quite differently. Yes, this stabilisation system recognises camera shake using its sensors, but modifications are made when the image reaches the image sensor.
This is achieved by zooming the image until it’s larger than the image sensor and then later scanning within the image to check for any movement, this is then countered by shifting the image in the opposite direction. but this method will degrade video quality and dip resolution as a result of zooming in.
Another way is to use an oversized image sensor where the image uses only about 90% of the chip’s area. The extra 10% of space is then utilised to recenter the image without any “cropping.”
Why is EIS a better option?
As the lens doesn’t move with EIS, the process of capturing each frame in a video is never slowed down by malfunction mechanical parts. EIS just has to adjust the image, which results in much smoother video output.
Also, EIS systems have the capability to predict the shift of the next frame, making a huge difference in video quality. While moving, the camera determines the direction in which you are moving, and if it determines that an object is moving in a single direction, EIS can set the next frameshift as needed. which lets you shoot a much smoother video.