Counterbalanced Image Stabilizer

Counter-Balanced image Stabilizer

 

      This camera-shake compensating mechanism works passively and requires no electrical power, gyros or warm-up time.  Developed by Steve Hines in 1977.  U.S. Pat. 4,290,684 assigned to Eastman Kodak.

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The image stabilizer in a clear camera body, showing the lens, film and holder, and three parallel support rods.  The rods are supported by an intermediate frame.  The lens and film counter balance each other on opposite ends of the three rods which are the same length as the focal length of the camera lens, so as to not over or under correct image smear.

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When the the camera body pitches up or down, or yaws left or right, inertia gives the mechanism’s support legs the tendency to remain at their previous angle.  As a result, the lens remains on a line between the object and its image on the film.  The camera in this animation is tilting through ±5° for illustration, however virtually all camera shake occurs within ±1°.

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Pitch or yaw	Defocus*, mm standard mechanism (smaller is better)	Defocus*, mm Hines’ mechanism (smaller is better)
0°	0.0	0.0
1°	1.15	0.015
2°	2.3	0.061
3°	3.46	0.137
4°	4.62	0.224
5°	5.9	0.381

 

 

 

 

*Change in lens-film distance, measured 57mm off axis, and based on a 100mm focal-length lens.

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What it provides:

 

      Pitch and yaw camera motions have the most serious effect on image smear.  Tipping a camera down 1°, has the effect of lifting an object at 50 feet, 10 inches.  This shake-mechanism compensates for five times this amount in both the pitch and yaw directions.

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      This mechanism can withstand, but is not affected by, translational motion (being bumped).

 

 

The concept applied to a 110-format camera:

 

       The film is stationary and the lens is counterbalanced with an offset added weight.  

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