Whether it is about Photography or Cinematography, taking a blurry image or shaky footage would be the worst nightmare for you. But no matter how experienced you are in photography, if you are shooting handheld, there would be some shake which might ruin the picture. Hence, image stabilization technology was developed first to address this problem and save you from clicking blurry images. And today, it works like a charm. But do you know how stabilization works? And which stabilization is perfect for which situation? What is the meaning of “5 axis of image stabilization” or “5 stops of image stabilization”. To explain all your queries, we have put together a detailed analysis of how image stabilization works.
First, we are going to discuss the stabilization axis. The most commonly used stabilization is the 2-axis stabilization. And these two axes are yaw and pitch. These movements are caused when the whole camera is not moving, but the angle is changing. It is more like, the camera is attached to a single anchor point and moving up and down, meaning the pitch movement or left and right, meaning the yaw movement. Moreover, when you press the shutter button, there is a bit of a rolling effect on the camera caused by the button press. This role is the 3rd axis. Then comes the 4th and 5th axis, which is the horizontal translation and vertical translation. It is more like the camera is not fixed to an anchor point, and the whole camera body moves up-down or left-right. These movements are quite common when capturing close-up shots or macros and also in videos.
Sensor-based Image Stabilization
Now, as you have understood the types of shakes that might occur while capturing footage, you might be thinking about how the camera detects those unintentional movements. Well, there is a Gyro detection sensor inside the camera that detects the shake. And this sensor is so fast and efficient that it can quickly detect even a slight movement in almost no time and send the signal about the movement to the camera’s processor. After that, the processor analyzes the data and decides in which direction the sensor should move to compensate for the shake. And then, the processor sends the movement information or, in plain words, movement orders to the stabilization mechanism that is attached to the image sensor inside the camera. Hence, if you move the camera in one direction, your camera’s stabilization mechanism will move to the opposite direction to eliminate the shake. The same technique is followed for all 5 axes to counter every possible shake. And that’s how you get smooth footage. But there is only one problem with sensor-based image stabilization. And that is when you use a longer focal length lens, the sensor-based image stabilization is not very effective. That is where you need lens-based optical image stabilization.
Lens-based Optical Image Stabilization
When speaking of Lens-based optical image stabilization, it is found on the lenses, as the name suggests. If you look at the inner part of a lens, you will find that the lens is made of different glass elements and light has to pass through all the elements before reaching the camera’s sensor. So what if the lens glass element moves according to the camera’s shaking to compensate for unwanted movement? If that’s possible, the sensor would get a smooth image. Well, this is the main concept behind lens-based optical image stabilization. In some cameras, the sensor and the lens-based stabilization work in coordination to give you the best stabilization experience. However, both of these stabilizations can make the price of lenses and cameras go crazy. And to keep the price low, there is a cheaper version of stabilization called electronic image stabilization.
Electronic Image stabilization
So all the stabilization methods previously discussed were hardware-based stabilization. And now, we are going to talk about software-based image stabilization called Electronic image stabilization. In this method of stabilization, each frame is analyzed by the processor to determine the shake. Then the frames are matched and aligned by the processor, which creates a sense of stability in the footage. But the process involved a crop factor in aligning the footage frame by frame, which is one of the most significant issues with electronic image stabilization. From the definition, it is clear that electronic image stabilization works best for higher frames-per-second settings. Because more frames mean lesser movement per frame and thus the processor needs to work less for aligning the frames. This is why cameras with higher fps like the GoPro and iPhones use electronic image stabilization. But for bigger cameras and lesser fps, electronic image stabilization is not so effective.
Now let’s talk about stabilization “stops”. But first, let’s understand some rules of photography. To eliminate camera shake to a level that your footage doesn’t look blurry, the rule of thumb is to set the minimum shutter speed at 1 by the focal length of the lens you are shooting with. So if you are using a 200mm lens, you must set the shutter speed at least to 1 by 200th of a second while shooting handheld. But the problem is shooting at a higher shutter speed reduces the amount of light entering the sensor. And if you slow down your shutter speed, you end up taking blurry images while shooting handheld. So that’s a dilemma. And this is where image stabilization comes into the picture to solve your issue. Now we all know that image stabilization is usually measured in “stops”. But what is a stop, you might ask. In simple terms, these “stops” let you shoot at a slower shutter speed without blurring the image. For instance, you are shooting with a 100mm lens, and so you have to shoot at a minimum shutter speed of 1 by 100th of a second. Now if your lens or camera has a 1 stop of image stabilization, you can shoot at a shutter speed of 1 by 50th of a second and get the same result as the 1 by 100 shutter speed. Similarly, if you have 2 stops of image stabilization, you can shoot at a shutter speed of 1 by 25th of a second and get the same smooth image as if you were shooting at 1 by 100 shutter speed. So this is how image stabilization stops, lets you shoot at a slower shutter speed allowing more light to enter into the sensor.
So that was all about image stabilization. We hope you have a better understanding of the stabilization axis and stops. The stabilization technology is continuously improving. Besides, we have seen some better examples of image stabilization in the Olympus cameras. So, what new innovation would you like to see in image stabilization in the future? Let us know in the comment section.