New anti-shake tech
Anti-Shake for tripods?
Should you leave image stabilization on or off with your camera mounted on a tripod?
It's not a silly question. After hearing that stabilization was degrading tripod-steadied shots, Canon researched the issue and found that IS may actually try to "compensate" for steadiness. As the company's report noted, "When there's not enough motion for the IS system to detect, the result can sometimes be a sort of electronic 'feedback loop,' somewhat analogous to the ringing noise of an audio feedback loop we're all familiar with. As a result, the IS lens group might move while the lens is on a tripod, unless the IS function is switched off and the IS lens group is locked into place."
For this reason, makers of anti-shake lenses recommend that you turn off the system when the lens is mounted on a tripod.
But Canon didn't let it rest there. On a number of Canon IS lenses (listed below), the IS sensors can detect that the lens is being held steady, and automatically engage a "tripod mode" that detects and corrects for mirror slap and shutter movement at slow shutter speeds.
Canon "tripod-sensing" lenses (use with Mode 1 Image Stabilization):
EF 28-300mm f/3.5-5.6L IS USM
EF 70-200mm f/2.8L IS USM
EF 70-300mm f/4.5-5.6 DO IS USM
EF 300mm f/2.8L IS USM
EF 400mm f/2.8L IS USM
EF 400mm f/4 DO IS USM
EF 500mm f/4L IS USM
EF 600mm f/4L IS USM
Panning The World
Image stabilization works by measuring shake in two axes, horizontal and vertical, and then using corresponding horizontal and vertical optical movement to keep the image sharp.
But don't try following a moving subject like a bicycle rider-the motion sensors will do their damnedest to "correct" your panning motion, resulting in a totally blurry mess.
The answer is to disable the horizontal axis of stabilization, leaving only the vertical axis active. This lets you pan a moving subject, at the same time counteracting your up-and-down shakiness to produce a nice, smooth pan with a creamy blurred background.
This was the innovation Canon put in its IS lenses, and termed Mode 2 stabilization, activated by a switch on the lens. Sigma uses a similar approach.
Nikon has panning stabilization, too, but there's no switch. When the VR sensors detect smooth horizontal motion, it automatically puts the lens into panning mode.
All sorts of factors come into play with panning, most notably the ability of the shooter to keep a steady bead on a moving subject (made more difficult by SLRs' viewfinder blackout). It comes down to probabilities: an experienced shooter can expect to get more sharp pans with stabilization than without, but not a perfect score.
Keep in mind that panning stabilization won't give you sharper shots of any creatures that bound or bounce while running-they will still blur in the vertical direction.
(A) Up-and-down shaky: Shot without image stabilization, background blur curves and is uneven due to vertical movement of the camera during exposure. Rider is unsharp.
(B) On the level: Panning stabilization counteracts vertical shake for a sharp shot of the subject and smooth straight background blur.