There are times when you take what appears to be a great photo: a keeper; one for the portfolio. You import it into your editing software and start to prepare it for the big time: exposure, color, sharpness…wait a minute. Sharpness! When you zoom the image to 100%, there is a slight fuzziness to it. Yes, at screen size it looks sharp, but when you pixel peep, the apparently sharp lines are—not. There is a softness; a lack of clarity. What you are almost certainly seeing is camera shake.
Image by Dean Ayres via Flickr
Why we need image stabilization
Camera shake happens to us all. It is more likely to happen with a longer telephoto lens and a slower shutter speed, but can also happen if your shooting technique is less than perfect. There is, however, a piece of hardware that can help reduce camera shake. It goes by the acronym VR, or IS, or OS or…the fact is many manufacturers call it different names, but the function of the technology is image stabilization.
Image stabilization was born in the video business, where the move to smaller, better-definition cameras freed up videographers to shoot handheld. This required a means of reducing the inherent movement found when hand-holding. Canon was the first to market with image stabilization, adding it to their formidable range of broadcast video cameras. The technology eventually found its way to their still camera range too—particularly in their SLR lenses. Let’s take a look at the three main types of image stabilization technology available.
The effect of image stabilization
1. Lens stabilization
This is the primary choice for DSLR users. Known as optical stabilization, it is a direct offshoot of the aforementioned Canon video stabilization. Known as IS by Canon, VR by Nikon, and OS by Sigma, it uses tiny sensors and gyroscopes to predict the way your camera is moving. Then, using equally tiny motors, it attempts to counter that movement. Because the system is tied to the lens, it is thought to be the most efficient of the image stabilization technologies, and can give an extra four stops of stabilization to an image. This means that if shooting with a telephoto lens, the slowest shutter speed you can use to achieve good sharpness is about 1/250th of a second. With lens-based image stabilization, you may be able to use 1/30th or even 1/15th of a second.
The primary con to lens-based stabilization is that it is specific to the lens, and adds significantly to the cost of the lens.
Image by Benjamin Nagel via Flickr
Canon was among the first to bring stabilization to still photography
2. Sensor stabilization
Sensor stabilization was born of the digital age, and originally developed by the now-defunct Konica Minolta, but further developed by Sony who bought the technology. Sensor stabilization uses similar technology as lens stabilization, except the sensor and motors are attached directly to the camera’s sensor.
When movement is detected, the sensor moves to counteract it. The obvious advantage to this system is that it will work with any lens. However, due to the limitations on how far and how quickly you can move the sensor, the actual stop increase that you can gain is only 2-3 stops. This is still a significant advantage over not using any image stabilization.
Image by Damien Roue via Flickr
Sony uses sensor stabilization
3. Digital stabilization
This third option uses the processing power of the camera’s CPU to analyze the movement in the image in real time, and counteracts it using software. When the shot is taken, the image is cropped in to counter any movement. The more movement, the more cropping will occur. This technology was developed from lower-end video cameras, and is a low-cost solution found on more budget compact cameras. It is not as efficient as the previous two examples.
Image stabilization, as with many tools in photography, should not be seen as a cure to camera shake. Instead, it should be used more as a way to potentially reduce shake. It should be combined with good technique and understanding of shutter speed to improve sharpness in your shots.
A couple of final caveats: when using any type of image stabilization, remember to switch it off if it is not required. It can use considerable battery power, reducing your battery life. Also, switch it off if using a tripod. Image stabilization is constantly working. If your camera is locked onto a tripod, the lens or sensor is moving even though the camera is not, meaning you might actually reduce the sharpness.