Hines
Lensless Optical Viewfinder
Patented
Manufacturing License Available
The Hines lensless optical viewfinder uses a reflective optical system to project a bright frame around the scene. This lowers the cost and provides a viewfinder which cannot be scratched or fingerprinted.. The scene is viewed directly through the open hole and therefore provides the cleanest, sharpest image of any existing viewfinder.
The Hines lensless viewfinder in a various cameras.
Compact 35mm camera
Pocket camera
Cell Phone
The Hines accessory viewfinder on digital cameras that do not have optical viewfinders. Perfect for day time shooting when the LCD is washed out by sunlight.
A pop-up version for small sports cameras, and as an underwater finder.
As a user approaches the camera, the thin frame and struts on the back wall becomes out of focus and unobtrusive as the reflected frame line appears around the scene.
The interior shows the open rim of the concave mirror on the camera's front wall (right), facing the reticle on the back wall.
Camera buyers frequently make judgments about the quality of a camera based on the viewfinder, making the Hines lensless viewfinder ideal to boost sales of disposable cameras. The Hines bright-frame viewfinder is the size of any open-hole finder, used in many single-use camera. The Hines viewfinder provides the consumer a scratch-free optical viewfinder in an affordable camera. The Hines viewfinder provides a manufacturer's advantage to set the camera apart from the competition, lowers the manufacturing cost, and supports a higher selling price, and provides an advertisable feature for increased profit.
The open shells of the molded camera body show the rectangular reticle in the back wall (top right), and the spherically curved rim around the opening in the front wall, which creates a perimeter rim of a magnifying mirror. Before assembly, these parts are aluminized to make them more reflective (the only recurring manufacturing cost of the finder). The rectangular reticle is held in the rear opening by thin radial struts. When the camera is assembled, the reticle faces the concave mirror and together form a focused image of the reticle at the distance of the scene. The openings around the reticle provide eye relief for eyeglass wearers.
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Comments about the Hines Lensless Optical Viewfinder:
Bill Ewald, Optical engineer, awarded 25 patents at Eastman Kodak, taught optical engineering to 6,000+ students at the University of Rochester's Institute of Optics, and within Kodak: "Extremely impressive. If I were working for a camera company, I would be very, very interested. Everyone should be. After seeing the models, I certainly prefer it over any Albada system."
Paul Ruben: Optical engineer, formerly head of Eastman Kodak's lens design group, responsible for viewfinder systems: "Not only does it aid the photographer by accurately delineating his field of view, but will be useful to any camera manufacturer who is trying to reduce the cost."
Fred Bushroe: Optical engineer: "...elegantly simple", "a parallax free viewfinder that is impossible to degrade with finger print smudges", "I tested it with glasses and it worked fine. Plenty of eye relief", "... important and novel". ."It has the potential to become a new standard."
Antony Brown: Photographer, London: “The principle is so brilliant in its simplicity.”
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- - - Viewfinder comparisons. Notice relative image sizes - - -
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Hines Lensless Optical Viewfinder
The Hines Lensless Viewfinder provides all of the advantages of the Albada finder with near the zero cost of the open-hole finder.
Scene light (blue) passes through the open hole unaltered. Scene light also illuminates the reticle RT in the back window and is reflected (yellow) to the rim of spherical mirror SM, around the front opening, where it is focused and reflected to the eye to appear to be at the scene.
This illustrates the view of a tripod-mounted camera as the photographer's eye moves around while finding the center of the viewfinder.
The image of the scene is unaltered, therefore is big, bright and in focus. The relative motion of the out-of-focus front window while centering the eye is of no consequence because the bright frame is fixed on the scene and represents the area photographed by the camera lens.
Without the projected rectangle, the photographer would think the camera was framed on the area of the shifting fuzzy window.
Advantages:
• Projected frameline shows the area being photographed.
• Bright unaltered view of the scene.
• No motion parallax between projected frame and scene.
• No lenses to degrade focus or strain eyes.
• No lenses to cause internal reflections.
• No lenses to cause color fringes.
• No lenses to scratch or fingerprint.
• No lens edges to cause flare.
• No reduction of image size.
• The "other" eye can remain open during framing.
• No larger than any open-hole viewfinder.
• Eye relief for eyeglass wearers.
• Near zero cost.
Disadvantage:
• Window approximately 15% larger than lens viewfinders.
Hines Lensless Viewfinder: Light from the scene passes directly through the open front hole of the Hines finder to illuminate the reticle on the back wall. The reticle frame in the back window, being so thin and close to the eye, is out of focus and unnoticed. The photographer views through the openings of the frame and sees the focused reflection of the frame in the rim of concave mirror around the front window.
The front window of any viewfinder is less than 2 inches from the eye, creating soft focus edges which are approximately equal in width to the pupil diameter. The sharply-focused image of the bright frame is superimposed over the soft-focus edge of the front window. On first using the Hines viewfinder, the reaction of most is surprise when looking through a hole, to find a focused bright frame. It seems like magic.
*Note to engineers: The best optics are the ones left out. Optical systems are only compromised in cost and quality by adding more elements. Compare the MTF of a scene viewed directly or through any open-hole viewfinder, to the degraded image when looking through any viewfinder using lenses. The reflective optical design of the Hines lensless viewfinder adds the frame line to the open hole without degrading the image of the scene.
Open Hole Viewfinder
The scene is viewed, unaltered, through the open hole. The front opening is very out of focus, and shifts relative to the scene as the eye moves, yet is the only reference for framing the camera, resulting in being virtually useless.
A small sample of open-hole viewfinders found in many single-use cameras.
The image is big and sharp; however, the front opening is severely out of focus, eliminating any accurate reference for framing. .As the eye centers on the viewfinder of this tripod mounted camera, the apparent frame shifts around so that the photographer has no way of knowing which part of the scene will be photographed.
Advantages:
• Bright unaltered view of the scene.
• No lenses to degrade focus.
• No lenses to cause reflections.
• No lenses to cause color fringes.
• No lenses to scratch or fingerprint.
• No lens edges to cause flare.
• No reduction of image size.
• The "other" eye can remain open during framing.
• Zero cost.
Disadvantages:
• Out-of-focus front edges do not accurately define the area covered by the taking lens.
• Motion parallax of the frame relative to the scene.
• Window approximately 15% larger than lens viewfinders.
Open-hole viewfinder: Light from the scene passes directly through the open finder. Because of the out-of-focus front edges and motion parallax, a simple open hole cannot accurately indicate the aim of a camera. .
Reverse Galilean Viewfinder
The Reverse-Galilean finder is found in 99% of single-use cameras and many reloadable cameras, and in concept is Galileo's 1609 telescope, turned around and used in reverse.
Only a single negative and positive lens are required to form the viewfinder, as seen in this one-piece molding from a Kodak camera.
Notice that the image is smaller.. The front opening is severely out of focus, eliminating any accurate reference for framing. As the eye moves behind the viewfinder of the locked off camera, the apparent aim of the camera shifts due to motion parallax. The image is shown out of focus which is avoidable; however, is more often the case than not.
Advantages:
• Approximately 15% more compact than open-hole finder.
Disadvantages:
• Smaller image, making it hard to see.
• Out-of-focus front edges do not accurately show the aim of the camera.
• Motion parallax between the finder's front window and the distant scene as the eye shifts past the finder.
• Image distance often focused too close for comfort.. Users must squint to bring scene into focus.
• Focus of image can vary from center to corner.
• More expensive than open hole.
• Reflections, from uncoated lenses.
• Simple 2-element design creates color fringes.
• Flare from edges of the lenses.
• Lenses can be scratched or finger printed.
The image size in a reverse-Galilean finder is reduced. The smaller the image, the harder it is to see and judge the composition.. Further, although manufacturers can set the focus of the viewfinder's image at any viewing distance, too often the image distance is set too close to be viewed sharply by people wearing bifocal glasses. Consumers have been given this choice for so long that they have become inured to the problems of reverse-Galilean finders.
The Albada finder is an upgraded Reverse-Galilean finder.. Scene light (blue) passes through the two lenses which minifiy the image (typically to 33-85%). Scene light also illuminates the reticle on the eye lens and is reflected (yellow) to the concave reflective portion of the front lens, and then reflected to the eye as being in the scene.
The Albada finder is found in mid-priced consumer cameras; however, is too expensive for single-use cameras. An aluminized reflective frame is deposited on the interior surface of the eye lens. The concave side of the front lens is partially aluminized to act as a magnifying mirror to focus the image of the bright frame; however, dims the brightness of the scene.
The image is minified by the lenses. The position of the soft-focused front edge of the finder shifts with eye movement; however, the bright frame shows the part of the scene being photographed. Internal reflections between lenses can be distracting.
Advantages:
• Projects a bright frame into the scene to indicate the field taken by the camera lens.
• No motion parallax of the projected frame relative to the scene if the eye moves behind the finder.
• Approximately 15% more compact than open-hole finder.
Disadvantages:
• Lenses cost money.
• Smaller image, making it hard to see.
• Image distance often set too close for comfort.
• Focus of scene can vary from center to corner.
• Image is dim due to mirror coating on front lens.
• Reflections, from uncoated lenses.
• Simple 2-element design creates color fringes.
• Flare from the edges of the lenses.
• Lenses can be scratched or finger printed.
• Too expensive to use in single-use cameras.
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- - - End of comparisons - - -
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Hines' original lab notebook entry for this invention.
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Consumers have not expected to find projected-frame viewfinders in single-use cameras, having seen only minifying lens finders and simple open holes. The patented Hines lensless optical viewfinder provides the projected frame at near zero cost. The Hines finder provides a novel and truly useful feature, perfect for single-use cameras.
For further information, see:
• SPIE's OE Magazine, May, 2005, p. 28.
• Photo Imaging News, June 14, 2004, Vol. 21, No. 13, p. 6.
• Photo Marketing Association News, Oct. 2001, Vol. 77, No. 10.
• U.S. Patent 6,122,455 (includes zoom version)
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Hines
Lensless Optical Viewfinder:
This is a technology announcement and license offer. This is not a product being offered for sale to end users. HinesLab is seeking a licensee. Camera manufacturers are invited to contact Steve Hines to discuss licensing at:
Glendale, California, USA
phone: 818-507-5812
email: Steve@HinesLab.com
www.HinesLab.com/LenslessVF.html
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