Tuesday, August 2, 2011

Digital Photography - Optical Image Stabilization

In this article, we are discussing the world of digital camera optical image stabilization. This technology has been around since first introduced in 1995, however, it just recently made its way into the amateur photographer market of lenses and cameras.

Lens Stabilization - Lens stabilization is a technology used in some camera manufacturer's lenses where the recorded image is stabilized by varying the optical path to the sensor. Right now, the two major companies having used lens stabilization the longest are Canon and Nikon. Canon calls their technology Internal Stabilization (IS) whereas Nikon calls theirs Vibration Reduction (VR).

Lens stabilization was never meant to prevent motion blur of the subject - just the minute shaking from the photographer hand-holding a lens, however, some lenses now include a secondary panning or active mode to compensate for those conditions.

A general rule-of-thumb with lens stabilization, you can expect to gain at least a two-stop improvement over a non-stabilized lens. For example, if you are using a 100 mm lens, you would not normally try to use a shutter speed of less than the reciprocal of the lens or 1/125th second.

By using lens stabilization, you could expect to handhold up to two-stops less or at 1/30th second. While the stabilized lenses of the big two are common in many respects, they are different.

Comparison - In a comparison test between a Nikon and a Canon stabilized lens, the Canon lens ended up being quicker and quieter, while the Nikon lens was smaller and lighter in weight. Both had the same maximum aperture, roughly the same focal length and basically, the same price. But it didn't stop there.

Canon's IS lenses have two modes, Mode 1 and Mode 2. Mode 1 is for general photography where the lens elements float thereby compensating for camera shake along both the vertical and horizontal axis. Mode 2 is used for panned shots and when used, it deactivates image stabilization in the horizontal direction. The mode switch is a small ribbed slider switch located on the lens barrel.

On the other hand, Nikon's Vibration Reduction system detects smooth movement on the horizontal axis, interprets it as panning, and engages its compensatory motors accordingly. It does not need or use a switch to select a mode, so the Nikon lens is smarter in that respect.

How It Works - Both Canon and Nikon use the same basic technology. Both use two shake-detecting sensors to detect lens movement - one for yaw and one for pitch. The two sensors detect both angle and speed of the movement and sends information to a high-speed processor in the lens.

The processor interprets the detection signals, converts these signals to drive signals telling the lens group which way to move to counteract the shake, therefore creating a stable image.

Camera Stabilization - Some companies, such as Konica-Minolta, Pentax and Olympus build stabilization into the camera body itself instead of the lens.This works by moving the image sensor to counteract for the movement. While this method works well with shorter focal lengths, it does not work well with longer ones as the sensor can not move enough to counteract all the detected movement.

What The Future Holds - The big two in this field, Nikon and Canon are working on making optical stabilization both more responsive and available on a wider range of lenses. In the past, optical stabilization, whether built into a lens or camera body, did not function well at slow shutter speeds. Recently, some new developments in technology resulted in lenses working much better at slower speeds. As the technology gets less expensive to manufacture, both companies are working on building optical stabilization into their less-expensive lenses and I imagine one day in the not-too-distant future, it will be as common as auto-focus is now.

Summary - There are several advantages to using optical stabilization:

That is an important feature when trying to photograph inside certain buildings that do not allow tripods or flash photography.

- One is a photographer can be more responsive by not having to set a camera on a tripod to photograph at moderately slow shutter speeds.

- Two, the photographer in many cases no longer needs to lug around a tripod thereby lightning up the load.

- Three, it is easier now than ever before to get crisp sharp images hand-holding a camera system that employs some type of optical stabilization.

The last feature is important when trying to photograph inside certain buildings that do not allow tripods or flash photography.

If you are considering an equipment purchase or upgrade, look into purchasing either a lens or camera equipped with optical stabilization. Your slow shutter speed photos will improve by using this new technology.

If you liked this article, visit our website at http://www.sunlightmedia.net/sunlightmediatravelwritingandphotography/ for more tips and techniques.

Ron


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