| The problem:
| When used intentionally, image blur can be a powerful technique to help guide the viewer’s eye to the main subject of a photograph, set the object of interest apart from the background, or to emphasise rapid movement of an object. In most cases, however, it is just plain annoying. Image blur has ruined uncountable numbers of shots, and millions of times photographers have been angry about opportunities they thought they’d taken but in the end have lost. Sometimes this can be partly remedied through software – but in many other instances the shot is irretrievably damaged. One of the possible causes of image blur is camera shake. The hands that hold the camera always shake a little, although the photographer hardly ever notices this, and under normal conditions it rarely becomes apparent in the pictures taken. Especially when shooting with long focal lengths or when using slow shutter speeds, even slight movements of the camera can result in blurred images. |
|
Intentional blur. A low depth of field can accentuate the subject. |
As a rule of thumb, ordinary camera shake will not result in blurred images if the exposure time is not longer than the reciprocal of the lens's focal length. I.e.: If a 200mm lens is used, the slowest shutter speed which will probably enable shots without camera shake resulting in a blurred photograph is 1/200th second (figures in equivalent 35mm camera values). If lighting conditions require longer exposure times, the easiest and traditional way to avoid camera shake and thus blurred images is to support the camera on a tripod or a solid object. Tripods can be heavy and in most cases are awkward to carry around, so chances are that photographers will often wish that there was something else to steady their grip on the camera without having to shoulder an extra weight.
Photo captured with image stabilisation. |
Unintentional blur due to camera shake. |
The solution:
Especially for low-light situations or when shooting with long-focus lenses, Olympus has developed a mechanical image stabilisation unit to prevent image blur caused by camera shake. This image stabilisation unit detects involuntary hand shake and corrects it. It enables the use of shutter speeds of up to five EV steps slower than without it, thus making it a lot easier for the photographer to obtain clear shots – even in low light situations or at long focal lengths.
And as it is built into the camera body it works with any Four Thirds lens attached. This spares the photographer the worry of having to decide before each lens purchase whether image stabilisation is required or not: It’s integrated in the camera, and that’s it. This means: No more worries, no additional expense for lenses with a stabiliser. |
|
How the image stabilisation unit works:
At the heart of the built-in image stabilisation unit – developed and designed independently by Olympus – is an Olympus-exclusive Supersonic Wave Drive (SWD) motor with excellent responsiveness and controllability. It uses the information about camera shake gathered by a newly-developed sensor that detects and analyses hand shake vibrations. To compensate for the shaking a piezoelectric element moves the image sensor accordingly.
 |
 |
Above: Components of the Olympus IS unit.
Left: An example of the built-in IS unit, which also incorporates the SSWF and image sensor. |
Depending on the user-selected mode, this happens either along both the x and y axis or only along the y axis. The former is the default for everyday photo situations, whereas the latter is useful when the photographer follows subjects with the camera, e.g. a car racing by, where camera movement along the x axis is intended.
Image stabilisation is even useful for capturing moving subjects.
 Find here older information regarding this topic
|
