Apparatus and method for minimizing red-eye in flash photography

• US 4,285,588 A
• Filed: 07/24/1980
• Issued: 08/25/1981
• Est. Priority Date: 07/24/1980
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Mir, Jose M.
• Primary Examiner(s): Adams, Russell E.
• Application Number:
  US06/171,639
• Time in Patent Office: 397 Days
• Field of Search: 354/126, 354/137, 354/145, 354/33, 354/35
• US Class Current: 396/158
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/05 Combinations of cameras with electronic flash units
• CPC Class Codes: G03B 7/087 for control of both exposure time and aperture

Abstract

Apparatus and method for minimizing a red-dot artifact in the eye of a flash photograph subject employs a subject conditioning pre-flash, predeterminedly preceding the camera picture-taking operation, to reduce the pupil size prior to exposure flash and shutter actuation.

Claims

1. In photographic apparatus for recording still pictures with supplementary illumination and including shutter means actuatable to an aperture-open condition and to an aperture-closed condition, flash means actuatable for providing supplementary illumination and means for actuating said shutter and flash means to initiate and terminate an exposure period of a picture-taking operation, the improvement comprising means for providing a subject-conditioning, illumination pulse which is of a predetermined energy and commences a predetermined period prior to the initiation of said exposure period to effect a substantial reduction of subject'"'"'s eye-pupil diameter, said predetermined period having a magnitude in the range of from about 0.35 to about 0.60 seconds.

4. The invention defined in claims 1, 2 or 3 including means for adjusting said predetermined period.

2. In photographic apparatus for recording still pictures with supplementary illumination and including shutter means actuatable to an aperture-open condition and to an aperture-closed condition, flash means actuatable for providing supplementary illumination and means for actuating said shutter and flash means to initiate and terminate an exposure period of a picture-taking operation, the improvement comprising means for providng a subject-conditioning, illumination pulse which is of a predetermined energy and commences a predetermined period prior to the initiation of said exposure period to effect a substantial reduction of subject'"'"'s eye-pupil diameter, the generating energy for said illuminating pulse being at least 1.5 joules.

3. In photographic apparatus for recording still pictures with supplementary illumination and including shutter means actuatable to an aperture-open condition and to an aperture-closed condition, flash means actuatable for providing supplementary illumination and means for actuating said shutter and flash means to initiate and terminate an exposure period of a picture-taking operation, the improvement comprising means for providing a subject-conditioning, illumination pulse which is of a predetermined energy and commences a predetermined period prior to the initiation of said exposure period to effect a substantial reduction of subject'"'"'s eye-pupil diameter, the generating energy for said illumination pulse being about 3.0 joules and said subject conditioning pulse being of about 1 millisecond duration.

5. For use with photographic apparatus of the type adapted for recording still pictures and having shutter means actuatable to a light-blocking and to a light-passing condition and means for actuating said shutter means to effect a picture-taking operation, an improved flash device for providing supplementary illumination during said picture-taking operation, said device comprising an actuatable source of flash illumination and flash control means, operatively associated with said flash illumination source and connectable with said actuating means of said photographic apparatus, for providing a first subject-conditioning flash pulse and second scene-illuminating flash pulse during a picture-taking operation, said first pulse preceding said second pulse by a period sufficient to allow a substantial reduction of subject'"'"'s eye-pupil diameter.

6. The invention defined in claim 5 wherein the magnitude of said period is in the range of from about 0.35 to about 0.60 seconds.

7. The invention defined in claim 5 further including means for adjusting said period between said subject-conditioning flash pulse and said scene-illuminating flash pulse.

8. The invention defined in claim 5 wherein said first pulse has a generating energy of about 3.0 joules and a duration of about 1 millisecond.

9. An improved method for flash photographing subjects in a manner minimizing red-eye artifacts, said method comprising pre-flashing the scene to be photographed with a subject-conditioning flash pulse and, within a period in the range from about 0.3 to about 0.65 seconds after said light pulse, effecting picture-taking flash illumination and recording.

10. The invention defined in claim 9 wherein said subject conditioning light pulse has a generating energy of from about 1.5 to 3.0 joules.

11. The invention defined in claim 9 wherein said subject-conditioning light pulse has a duration of about 1 millisecond.