What is image stabilization? OIS, EIS, and HIS explained
Smartphone camera technology is built from many parts, from sensors and lenses to laser focusing systems. Image stabilization is, increasingly, one of the fundamental building blocks of a great smartphone camera.
Image stabilization is important for, well, stabilizing your images. Without it, your snaps and selfies come out a blurred mess, and videos look like they’ve been shot for an 80s B-movie. You see, a camera’s shutter has to be open to capture light. While this is happening, the slightest movement can smear your image. This is especially true when the shutter is open for a long time, such as when shooting in the dark.
The luxury of image stabilization has become a necessity.
With HDR and night modes being more prevalent in our smartphones, the luxury of image stabilization has become a necessity. Virtually all smartphones provide image stabilization on at least one camera. However, there are a few different types of image stabilization. Here’s everything you need to know about them.
Optical Image Stabilization (OIS)
OIS is a hardware solution that uses a micro-electromechanical system (MEMS) gyroscope to detect movement and adjust the camera system, accordingly. For example, if you are holding your smartphone and your hand moves slightly to the left, the OIS system will pick up on this and shift the camera slightly to the right.
This, being a hardware solution, doesn’t require any cropping of the image, meaning that the phone uses a full sensor readout to capture the photograph. A byproduct of this is zero-distortion video since you don’t get the jelly-effect that comes from digital stabilization. OIS makes for far more natural video too, since you’re not applying an effect to the video.
Constructing good OIS hardware isn’t cheap, which adds to the bill of materials cost and ultimately means you’ll pay more for your OIS-equipped smartphone. It also turns a typically static element, the camera module, into another moving part. It’s very rare, but sometimes the moving parts in an OIS system can malfunction.
OIS is a useful tool to have whether you are shooting video or photos. It’s particularly adept in low-light scenarios, where the camera’s shutter may be open for longer. Without OIS, this can result in blurry photos due to slight hand movement. With OIS enabled, slight shakes are canceled out, making for crisper photos. The same goes for telephoto cameras, where the smallest of shakes are amplified due to the far narrower field of view.
Continue reading: OIS explained!
Electronic Image Stabilization (EIS)
EIS is an attempt to do what OIS does, but without the physical hardware. This works by utilizing your smartphone’s accelerometer to detect small movements. The camera software interprets those movements and aligns each frame together. For images, this is crucial in the processes of HDR and night mode, where the camera is taking multiple pictures in a short space of time.
For video, the software will find a point of high contrast and attempt to keep that point in the same part of the frame. More modern examples of EIS use machine learning to detect the subject and lock the stabilization, accordingly. A common trade-off with using EIS is that it can produce unnatural-looking distortion from slight changes in perspective. This is what’s known as the jelly effect.
Arguably the biggest drawback of this stabilization method is the crop that is required for the process. With EIS enabled, you no longer see the full sensor in the output. The edges of the sensor image are used like a buffer zone. The stabilized image can be moved around within this margin, keeping the subject stationary in the frame. Without the buffer zone, you would cut off the edges of the image as the stabilization moved around.
Hybrid Image Stabilization (HIS)
HIS is, as the name suggests, a combination of both OIS and EIS. It’s a good all-round solution. OIS provides the basic hardware stabilization and then EIS is used to further smooth out the video footage. Due to the benefit of having OIS, the EIS crop factor doesn’t have to be as extreme. The buffer around the edges of the image can be smaller, resulting in a subtler crop and less of an impact on the final frame.
For images, there’s not really any benefit to a hybrid system. The OIS part will ensure shake-free shooting in all the desired scenarios. Although EIS could be switched on for added stability with HDR and multiple exposure night shots.
If you’re wondering what the results look like, here’s an example from Google’s Pixel 2, which was the Android giant’s first phone to use an OIS and EIS hybrid system:
What if Hybrid isn’t enough?
If you’re still unhappy with the smoothness of your smartphone video footage, one final trick would be to use a gimbal. These are essentially large gyroscopes that, when balanced correctly, keep your phone in the same orientation. Motors are used to counteract the movement of your hands by moving the camera in the opposite direction. However, the results are not always better than your smartphone’s image stabilization.
Gimbals give the added benefit of letting you control the motors to create smooth pan and tilt movements. There is usually a joystick built into the handle to let the user manipulate the gimbal’s movements. These gimbals cost anywhere from $80 to $140 depending on the make, model, and accessory kit. That’s quite a bit of money for something that definitely won’t fit in your pocket.
Continue reading: The best smartphone gimbals!
What you need to know about image stabilization
If you want the best of both worlds, the hybrid methid is a no brainer. You get the natural stability in video thanks to the OIS element and EIS will take care of the rest. Thankfully, all main cameras on smartphones have some form of EIS, with the majority also having OIS. These days, as long as you’re spending reasonable money, you don’t need to worry about stabilization quality. Things like dynamic range, the field of view options, and color processing are all going to have a far larger effect on your final footage.
If you have to choose between OIS and EIS, pick the former.
If you have to choose between OIS and EIS, pick a camera phone that offers the hardware-based solution. It’s less artificial-looking for video, and far more effective for still images. If you’re after a good quality zoom lens on your next smartphone, make sure that said lens has OIS. Ultra-wide lenses don’t require OIS in video modes due to the larger field of view in combination with EIS. This means that whilst there is a crop, it’s nowhere near as extreme as if it were applied to a longer focal length.
Unless you’re looking to create short films with your mobile, the need for a gimbal is becoming less and less thanks to the improvements being made in Hybrid IS technology. Even modern mid-range phones offer great image stabilization capabilities.
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