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How do cameras stabilize the image they capture?

Motion blur caused by camera shake can be very frustrating for anyone, especially when zooming in. If you have ever tried to take a photo holding the handheld camera with slow shutter speeds, you will know exactly what we mean, although even on a PC webcam this is noticeable by the small vibrations that the PC or our arms resting on the camera. table provoke. So how do you still get sharp photos or videos? You have three options: use a tripod on the ground, increase the shutter speed … or take advantage of image stabilization technology.

What is image stabilization?

Image stabilization is a specialized technology built into the hardware of cameras, and more specifically their lenses, that helps minimize blur caused by movement or vibration. Different manufacturers call this technology in different ways, such as in cameras:

  • Canyon: Image Stabilization (IS).
  • Nikon: Vibration Reduction (VR).
  • Tamron: Vibration Control (VC).
  • Sigma: Optical Stabilization (OS).
  • Sony: Optical Steady Shot (OSS).
  • Pentax: Shake Reduction (SR).

Regardless of the name, the technology has the same effect and is similar across all manufacturers. The benefit is that it allows you to capture a photo or video much sharper at a slower shutter speed or without a tripod that keeps the camera still. Enabling a slower shutter means better image quality because you can use a lower ISO value (less noise).

Stabilization on the camera lens

Image stabilization scheme

Lens-based image stabilization works through an element called a floating lens. Vibration (or camera shake) is detected by gyroscopic sensors, and the lens is moved accordingly to mitigate the effects. Many lenses often incorporate a panorama mode that allows stabilization only in the vertical axis to allow stable panoramic images, but has no effect in the horizontal axis.

This type of image stabilization has some advantages over that built into the hardware, especially at longer focal lengths and older DSLR cameras. For example, the automatic focus of a camera is more precise when the image is already stabilized, and also while you take the image you will also see it already stabilized, which allows you to better capture the details of the image or video that you are going to take beforehand; otherwise, you would see a more shaky and poorly detailed image when you take it.

This technology also has some disadvantages, such as that it can only counteract the effect of movement in the horizontal and vertical axes, which means that no form of rotation effect can be detected or stabilized. The second disadvantage is cost, as each lens must be equipped with its own image stabilization system rather than this technology being built into the hardware of the camera itself, and the cost of the lenses is higher.

Stabilization in camera hardware

Hardware Image Stabilization

Hardware image stabilization generally works through sensor switch technology. While the technology itself is quite sophisticated, the concept is very simple: the sensor moves to counteract camera shake, similar to the floating element in lens-based stabilization. Gyro sensors inside the camera detect movement and send the information to actuators that move the camera’s image sensor in the opposite direction.

The difference is that sensor switching can also counteract rotational movement, and in fact most image stabilization technology is sensor-based and works on five axes: horizontal, vertical, roll, pitch, and yaw. The horizontal and vertical axes are when the camera moves up and down or left and right. Roll is when the camera rotates along the horizontal axis, while pitch is when it rotates vertically, up or down. Yaw is when the camera is tilted left or right.

The obvious advantage of this type of stabilization is the three additional axes of compensation; Being able to account for rotation means that hardware stabilization is generally more versatile and accurate than lens-based stabilization. It also means that the camera does not have to include lenses with this function, so it is also cheaper to manufacture and also lighter.

Sensor-based stabilization has also led to the advent of other useful camera capabilities, such as face tracking modes, which is very useful on a webcam or smartphone selfie camera. In addition, with the help of a GPS module, there is also the star-tracking mode (such as Pentax’s Astrotracer) that allows the camera to use the sensor to track the rotation of the Earth, which means that times of much higher exposures during astrophotography.

However, this method has the disadvantage of not stabilizing the view through the optical viewfinder, which means that when taking the image or video we could see it blurry even if the image comes out well later. This is not a problem in modern cameras, since the electronic viewfinder takes the image directly from the sensor and therefore the image will already be stabilized.

Digital image stabilization

Digital image stabilization

Digital image stabilization, also known as electronic or software stabilization, is used in some cameras, mainly video. This technique analyzes each frame of the video for movement and shifts them pixel by pixel to produce a stable video, reducing camera shake and making the video appear sharper. The same can be done directly by software, such as Adobe Premiere.

One downside to this technique is that it requires cropping the image size to achieve this, as pixels outside the frame must be used as a buffer and must be clipped to allow for stabilization. Generally, the greater the vibration or movement, the greater the clipping and the lower the resolution.

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