Understanding Anti-Shake Camera Technology by Alfred DeBat
by Alfred DeBat
Rating: 7 / 10These days, a lot of manufacturers are boasting about their anti-shake features. Here's the facts behind the feature.
The latest crop of digital cameras offers “anti-shake” features designed to produce steadier handheld shots in low illumination. The aim is to eliminate slight camera movements at low shutter speeds that produce unsharp images. Anti-shake modes are also important when making handheld exposures with extended-range telephoto zoom lenses, since an extreme telephoto setting will greatly magnify any small vibration.
Cameras with this option usually indicate a need for the anti-shake feature by displaying the icon of a vibrating or shaking upheld hand in the viewfinder. Often there is an illuminated button or switch with the same icon, which turns it on and off. Several different technologies can be used to accomplish anti-shake; however, the results are not the same among them.
Sensor Chip Compensation: One of the most advanced technologies is a system that actually moves the camera’s sensor chip in a manner that counteracts the camera’s movement. The system can’t accommodate major swings, but works very well with typical handheld tremors at slow shutter speeds. Several Sony digital cameras employ this system, as well as discontinued Konica Minolta models. (The system was originated by Konica Minolta, and licensed to Sony after Konica Minolta stopped manufacturing digital cameras.) Sony calls the feature Super SteadyShot Optical Image Stabilization.
The extended-range 36-432mm zoom, 7-megapixel Cyber-shot DSC-H2 and Cyber-shot DSC-H5 models employ this technology, as well as several smaller Sony point-and-shoot cameras, such as the ultra-compact Cyber-shot DSC-T10 and super-slim Cyber-shot DSC-T50.
Optical Image Stabilizer: A different approach is using a pivoting lens element within the camera lens, which compensates for handheld movements at low shutter speeds. This system was developed by Canon for some of its EOS SLR film camera lenses. (These lenses are identified by IS for “image stabilization.”) Of course, Canon EOS SLR lenses can be used with the many interchangeable-lens Canon digital SLR models. Canon also incorporates the same anti-shake feature on many of its point-and-shoot camera models with built-in lenses, including 35-210mm zoom, 10-megapixel PowerShot G7; 28-105mm zoom, 7-megapixel PowerShot SD800 IS; and 35-210mm zoom, 7-megapixel PowerShot A710 IS.
Nikon has a similar but different system called Vibration Reduction (VR) Technology, which also employs moving optical components in the camera lens to compensate for the jiggles and vibrations during handheld exposures at low shutter speeds. The VR system is incorporated in some Nikon interchangeable SLR lenses, as well as point-and-shoot cameras. Most Nikon VR cameras offer users two modes: One is activated when the shutter release is pressed halfway, and another only during the actual exposure, which saves battery power. In-lens VR camera models include the 38-380mm zoom, 6-megapixel CoolPix S10; as well as the compact 36-126mm zoom, 8-megapixel CoolPix P3 and P4; plus the ultra-slim 35-105mm zoom, 7-megapixel CoolPix S7c.
Although both of these systems are sophisticated and excellent solutions to the anti-shake problem, they both have two drawbacks. In most cases, photographers are required to engage the system after noticing the Shaking Hand icon warning sign. Second, the system requires battery power, so if it is on continuously for all picture taking, it is needlessly sapping battery energy.
Digital Image Stabilization: Many point-and-shoot cameras employ the Digital Image Stabilization (DIS) solution to the anti-shake problem. In-camera software processes the image after it is captured and electronically shifts pixels to mimic the camera’s movements and eliminate picture blur. The results are good, but not as effective as moving the sensor chip or optics for image stabilization at the moment of exposure. Among models employing DIS are the extended-range 28-504mm zoom, 7-megapixel Olympus SP-550UZ, and the 38-190mm, 7-megapixel Olympus FE-240. Both of these cameras, in addition to a high ISO anti-shake mode, have a Digital Image Stabilization Edit mode, which permits in-camera image retouching. The camera’s gyro sensors track its vertical and horizontal movement during an individual exposure and use the data to sharpen the blurred image immediately afterward.
Picture Stabilization: Probably the least expensive method for reducing handheld blurs is Picture Stabilization (PS). When the camera’s auto-exposure system senses that a slow shutter speed is required, it kicks up the sensor chip’s sensitivity. Since sensor chip sensitivity is adjustable, cameras can automatically move it from ISO 100 (the normal, bright-light sensitivity) to as high as ISO 3200 in some digital point-and-shoot models. (By the way, “ISO” is just the photo industry’s way of identifying film sensitivity. It was adopted to compare sensor sensitivity in digital cameras.)
With higher ISO sensitivity, a faster shutter speed is automatically selected and the danger of manual camera shake is reduced. Some camera manufacturers advertise the same feature to halt the blurring of very active subjects in low illumination. Although this may sound like a neat solution for handheld exposures, it too has some serious drawbacks. Most digital cameras take their best, most colorful images at low ISO numbers. When pushed to extremes, such as ISO 1600 and ISO 3200, the camera sensors often produce grainy images with weak detail in shadow areas. So you may have sharper pictures, but at the cost of image quality. As in many other things, there’s no free lunch.
Fujifilm has a Picture Stabilization Mode on several models, including the 36-108mm zoom, 6-megapixel FinePix F30; 36-108mm zoom, 8-megapixel FinePix A800; and 28-300mm zoom, 6-megapixel FinePix S6500fd. Instead of a shaking hand, Fujifilm cameras use a vibrating man icon.
Pentax has several models with high ISO 3200 Digital Shake Reduction, including the 38-114mm zoom, 7-megapixel Optio M30, and the 37-112mm zoom, 10-megapixel Optio A20.
Samsung reports that its 38-270mm zoom, 7-megapixel NV7 OPS digital camera has two anti-shake functions: Optical Picture Stabilization (OPS) and Advanced Shake Reduction (ASR).
Casio has the 10-megapixel EX-Z1000, and the ultra-slim, 6-megapixel EX-Z60 with Anti-Shake Digital Picture Stabilization (DPS).
You can learn more about these and other cameras at manufacturers websites, including: www.canon.com, www.casio.com, www.fujifilm.com, www.nikonusa.com, www.olympusamerica.com, www.panasonic.com, www.pentaximaging.com, www.samsungcamera.com, www.sigmaphoto.com and www.sonystyle.com.