Camera shake

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Camera shake is a common problem in photography when telephoto lenses or long shutter speeds are used with a non-stabilized camera. The resulting images will appear blurry and smeared. This is generally seen as an unwanted effect, in contrast to motion blur where the subject will appear blurry due to motion.

To avoid images suffering from camera shake when hand holding a camera, photographers use the following rule of thumb: shutter time must be shorter than 1/focal length

For example, a lens with a focal length of 200 mm can be hand held at shutter times shorter than 1/200 sec. Digital SLRs generally have smaller sensors than 35 mm film, thus before using the 1/focal length rule, the equivalent 35 mm film focal length has to be determined.

All dSLR manufacturers offer camera bodies and/or lenses equipped with some kind of image stabilization to reduce camera shake and similar features can be found in many compact digital cameras. While this can increase the useful (ie. steady) exposure time a by several exposure stops, anti-shake features do not counter motion blur arising from moving subjects.