Bio-Feedback Autofocus


Bio-Feedback Autofocus



      This is an autofocus technique proposed by Steve Hines in 1976 to focus the camera lens to match the focus of the photographer’s eye.  As the photographer views the scene through the viewfinder, infrared scanning optics in the viewfinder determine the focus of the eye, and focus the camera to match.  This technique works where others do not, through glass windows, through screens and twigs, in bright sunlight, where the object is off center, etc.

      When the photographer looks at a subject through the viewfinder, infrared optics sense the eye’s focus and focus the camera lens to match. 



Bio-Feedback-AF-03-700-wAn early mockup used a rotating chopper drum to provide scanning light.



      A hand-held version used a small light as an infrared source.  Parallel lines on a liquid-crystal filter were sequenced to create a wave motion.  A line sensor was used to detect the direction of sweep of the light reflected out of the eye to determine the direction of focus.         A viewfinder modified in 1977 used IR LED’s sequenced to create the sweeping motion of light across the retina.  That sweeping light was reflected out of the eye to the line sensor to determine direction of sweep, and therefore whether the camera was focused too far or too close.


      Kodak did not pursue a patent after finding prior art in the Bausch & Lomb Ophthalmetron.  Today, this technology is found in hand-held auto-refractors in ophthalmologists’ offices where the device takes a reading on the eye to determine the prescription needed for eyeglasses.  


      This is not a product for sale, but is shown as an example of technology, developed by Steve Hines, which clients can now expect from HinesLab on a contract basis.  Please contact Steve Hines at:






ph. 818-507-5812