Lee teaches about IS/VR

Image Stabilization
IS Modes Image Stabilization (IS), also known as vibration reduction and anti-shake, is a technology that helps prevent digital photos from becoming blurred. IS reduces camera shake caused by hand movement, slow shutter speeds or when using a long telephoto lens without a tripod. Image stabilization is often found in consumer digital cameras with long telephoto zoom lenses. However it is available on an increasing number of cameras with short focal lengths. IS is also found on professional digital single lens reflex cameras, interchangeable lens and videocams. IS helps a photographer take handheld shots almost two stops slower than without it. It is important to point out that Optical Image Stabilization does not prevent blur if a subject itself is moving.
Optical vs. Digital Image Stabilization
Optical IS A camera with Optical Image Stabilization produces the best results. Unlike digital IS, Optical IS is hardware based. The camera typically has a built-in gyrosensor and microprocessor which detect camera shake as it occurs. If your camera has Optical Image Stabilization, it's adviseable to keep it turned on at all times. The only exception, as recommended by manufacturers, is to turn it off when using a tripod or other camera support. There are three types of Optical Image Stabilization modes, though not every digital camera with IS has three: Continuous, Shoot Only and/or Panning.
Digital IS Some cameras have Digital Image Stabilization, which simply boosts camera sensitivity (ISO) to obtain a faster shutter speed. There is no hardware involved. The higher the ISO, the greater the chance for image noise, which can degrade the quality of an image. In some cases where digital image stabilization is used, there in-camera processing, such as sharpening, to correct image blur.
------------------------------------------------------------------------------------------------
THE FUTURE OF LENS TECHONOLOGY
I recently agonized over purchasing the Canon 24-70 f2.8 lens OR the Canon 24-105 f4 IS lens. I have decided that f2.8 is the only way to go. Pro Glass traditionally has used an aperture of f2.8. More and more lens are coming with IS/VR flavors and F4. This is because Film was shot at ISO 100 and Digital is shot at ISO 400. Reducing the aperture increases “camera & subject motion” because you must lower the shutter speed to compensate. New cameras are being made with less Noise allowing us to raise the ISO instead of lowering the shutterspeed.
The other solution for reducing camera motion is Image Stabilization. HOWEVER:
IS won’t freeze the subjects action, only higher SS’s from larger apertures will
To blur backgrounds. Need wider aperture.
Higher quality optics. IS version normally lower quality (complexity fm more group elements!).
Due to the above, better performance with TCs. IS doesn't help.
AF with a 2x TC. IS doesn't help. Canon AF needs f5.6 to work
IS version usually creates dimmer viewfinder. DSLR have dimmer than film. Need Wide Aperture.
IS is of limited use on tripod.
Correcting for camera motion in the lens is a fairly new and changing technology. There are many false words used by manufacturers to describe it. There are tons of rumors on the internet for how to use it. Here is the bottom line.

-It can be a great new tool.
-It does not affect subject motion only the camera’s motion.
-Nikon & Canon have three different generations of this technology.
-Lens makers are offering lenses that were previously non-IS f2.8 version in IS f4 versions.
-Reducing the aperture WILL: dim viewfinder, reduce TC use, reduce DOF (bokeh) effects, increase subject blur.

Canon IS The Canon Image Stabilizer uses sensors to detect motion and generate a corrective signal to reduce blur caused by camera movement. An image-stabilizing lens group along the optical axis is shifted in response to the detected motion, providing effective cancellation of unwanted lens movement and vibration.

Nikon VR
The VR System works by adjusting the lens to compensate for camera shake and to make sure light from A converges on A’. Each VR Unit contains a VR lens elements and driving motors to make this happen. Nikon's first camera with a VR feature was the Nikon Zoom 700VR QD 35mm film compact camera released in 1994. The next product with the feature was the AF VR Zoom-Nikkor 80-400mm f/4.5-5.6D ED, an interchangeable lens for SLR cameras released in 2000. A major difference from current Nikon VR products is that it offered two modes—one in which the VR function is on from the time the shutter-release button is pressed halfway, and another in which it functions only during exposure.
In addition, the AF-S VR Zoom-Nikkor 70-200mm f/2.8G IF-ED and models released later have an “Active Mode” that effectively reduces camera shake when shooting from a moving vehicle and other similar situations. Subsequent interchangeable lenses have had VR functions such as the AF-S VR Zoom-Nikkor 200-400mm f/4G IF-ED with a tripod vibration-reduction mode, and the AF-S DX VR Zoom Nikkor 18-200mm f/3.5-5.6G IF-ED designed for digital SLRs. The AF-S DX VR Zoom-Nikkor 18-200mm f/3.5-5.6G IF-ED uses advanced, next-generation VRII technology, and it is the world's first lens that has achieved a VR effectiveness equivalent to about four stops in shutter speed.
When comparing in-lens and in-camera styles, the biggest difference is whether or not you can check VR effectiveness through the viewfinder. Generally, in-camera VR systems don't allow photographers to see how vibration will be compensated for through the viewfinder, while the in-lens feature that Nikon uses today does.

Lee Miller

“Light Your World Photography Classes”
“A Touch Of Color Photography”
tocphotography@adelphia.net
719-380-7301