Image stabilization figures are quoted in stops, where each stop means you can use a shutter speed twice as long as you otherwise could while keeping a handheld shot sharp. CIPA, the Camera and Imaging Products Association, publishes a standard test method so makers can state those numbers in a comparable way. The figure is a useful guide, not a promise for every situation.
What a Stop of Stabilization Means
A common rule of thumb says the slowest safe handheld shutter speed is about one over the focal length. At 100mm that suggests roughly 1/100. If a system claims 4 stops of correction, the idea is that you could stretch that to about 1/6 and still get a sharp frame, since each stop doubles the exposure time.
The key phrase is “could”: the benefit depends on you, the subject and the scene.
How the CIPA Method Works
The standard describes a repeatable lab procedure so different cameras and lenses are measured the same way.
- The camera is fitted to a shaking platform that reproduces typical human hand movement.
- Shots are taken at a series of shutter speeds with stabilization off and on.
- Blur in the resulting images is measured and compared against a defined sharpness threshold.
- The slowest shutter speed that still meets the threshold with stabilization on is compared to the one with it off.
- The gap, expressed in stops, becomes the stated figure.
The method also specifies conditions such as the test chart, the focal length used and the direction of motion measured.
Why Real Results Differ
- Test focal length: makers often quote the figure at a specific focal length, usually the long end of a zoom.
- Specific pairing: some figures apply only to a certain body and lens combination, especially where body and lens stabilization work together.
- Your own steadiness: breathing, stance and fatigue change the outcome.
- Subject movement: stabilization steadies the camera, not a walking person or a moving animal.
- Close focus: macro distances magnify small shifts, so correction can fall short of the quoted figure.
Using the Numbers Wisely
Treat CIPA figures as a way to compare products on one basis, and check the maker’s notes to see which body, lens and focal length they apply to. Then run your own check: shoot a static subject at progressively slower shutter speeds and note where your keeper rate drops. That personal limit is more useful than any lab figure.
Also remember that panning, tripod use and some video modes call for different stabilization settings. Many systems offer a mode for horizontal panning, and some advise turning correction off on a locked tripod.
FAQ
Does more stops always mean sharper photos?
No. It means more room for slow shutter speeds on still subjects. Moving subjects still need a fast shutter speed, and a higher figure does not change that.
Are the numbers comparable between brands?
They are meant to be when the CIPA method is followed, but check that the same focal length and pairing conditions are named. Confirm exact figures on the maker’s own page.
The Short Version
A stop of stabilization lets you double your shutter time, and CIPA gives a shared test method for stating how many stops a system offers. Use the number to compare, read the conditions, and find your own handheld limit by shooting.
