elements or the actual digital sensor, to redirect the optical path, therefore reducing blur.
Image Stabilization Sample Photos
Two photos taken at 1/8th of a second. The left photo was taken with no image stabilization and the right photo was taken with the Shake Reduction system on the Pentax K10D digital SLR.
4. Kinds of Image Stabilization
The first and most common kind of image stabilization is the optical or lens-based variety. The sensors and compensating elements are built into the lens. The benefit of this is that each system is tuned for the specific weight and focal length of that particular lens. The main drawback is that lens-based systems add weight and bulk to the lens assembly.
The second type of stabilization anti-shake system is actually built into the camera body. Similar sensors are employed to detect camera shake, but instead of moving lens elements to compensate for movement, the actual sensor is shifted. Tiny motors (servos) constantly readjust the position of the sensor to account camera shake. This sensor-level anti-shake system was first used in Konica Minolta's compact digital and digital SLR cameras, and later in the Sony A100 Alpha digital SLR. A huge benefit of sensor-level image stabilization is that any lens compatible with an image stabilized camera body immediately gains stabilization. One drawback is that anti-shake system failure means the whole body has to go in for repair. And although the current image stabilized digital camera bodies offer excellent results with wide angle and normal telephoto lenses, the benefits will diminish at longer telephoto lengths (200mm and longer).
5. What doesn't image stabilization help with?
It's very important to realize that although anti-shake technology is an effective tool, it is not a magic bullet. Sloppy photographic technique is not magically negated by flipping a single switch. Nor does it replace a tripod when exposure times become longer than about 1/3 of a second. Granted, some people can handhold with image stabilization down as low as 1/8 of a second. But that's either because they have impeccable technique and/or they're using a shorter focal length lens. Telephoto lenses magnify camera shake so they require shorter exposure times to ensure sharpness. The longer the exposure, the more likely it is that blur will be a problem, no matter what precautions are taken.
One thing that anti-shake technology might eliminate is the monopod. The benefits are largely the same, without the awkwardness and bulk of a stick attached to your camera. However, monopods and tripods also help support your camera - something image stabilization can't do. Some anti-shake systems behave erratically when mounted on a tripod. This is because the system expects a certain amount of motion, and overcompensates if there's no movement. Read your manual to find out the limits of your system - each one is unique.
In the end, image stabilization is yet another tool we can use to help us better capture what we see. Personally, I find I benefit most from the way the added steadiness helps me compose my shots - sharpness is just an added bonus. But I sometimes wish that turning off the image stabilization would also remove the added weight and size from my lens. Anti-shake isn't a must-have feature, but if being prepared for for anything is desired, it's another tool that may help you get better photos.
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