Stabilisation Stops
Stops tell you how much slower a shutter speed you can use by hand without shake. Each stop doubles the time you can hold the camera steady.
On this page 3 sections
Camera and lens specifications often say stabilisation is good for 5 stops or 7 stops. The number is the maker's claim for how much slower the shutter can be set while a handheld photo stays sharp. Each stop doubles the exposure time. One stop means twice as long, two stops means four times as long, and so on.
Example
Suppose 1/250 second is the slowest shutter speed that gives a sharp handheld photo without stabilisation. With 3 stops of stabilisation, about 1/30 second becomes possible. With 5 stops, about 1/8 second becomes possible. In a dimly lit room, that can separate a blurred photo from a sharp one.
How the figure is measured
Makers usually follow an industry test standard, in set conditions, with a particular lens at a particular zoom setting. The figure may apply to the lens alone, the camera body alone, or the two working together.
What it does not promise
Real results are usually a little lower than the listed figure, because the photographer's steadiness, the lens and the zoom setting all change it. The number says nothing about moving subjects, which need a fast shutter whatever the stabilisation. It describes photos, and video smoothness is not measured the same way. A higher figure is a bigger claim, not a guarantee.