Lensless Camera Viewfinder

...The Hines lensless viewfinder is an almost zero-cost alternative to the expensive Albada viewfinder to project a bright frame around the scene, to help the photographer accurately frame the picture.. The Hines viewfinder exceeds the quality of the Albada viewfinder because the image of the scene is undegraded by lenses which could be scratched or finger printed, yet provides a bright frame around the scene.

...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 single-use and reloadable film and digital cameras.. The Hines bright-frame viewfinder is the size of any open-hole finder, as in the Kodak Fling and FunSaver cameras, and the Fuji QuickSnap 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 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 large opening in the camera's front wall, which creates a perimeter rim of magnifying mirror. Before assembly, these parts are aluminized to make them more reflective (the only 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 scene appears to extend beyond the image of the frameline due to the diameter of the user's pupil.. The openings around the reticle provide eye relief for eyeglass wearers.

Comments about the Hines Viewfinder:

Bill Ewald, Optical engineer, awarded 25 patents at Eastman Kodak, taught optical engineering to 6,000+ students at the Univ. of Rochester's Institute of Optics, and at 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."

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 past and around 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 an illuminated frame.. It seems like magic..

.. *Note to engineers: The best optics are the ones you leave out.. Optical systems are only compromised in cost and quality by adding more elements.. Compare the image quality of a scene viewed directly, or through any open-hole viewfinder, to the degraded image when looking through any viewfinder using lenses.. The Hines lensless viewfinder adds the frameline without degrading the image of the scene.

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.

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 Reverse-Galilean finder is found in 99% of single-use cameras and uses 2 lenses (a negative lens in front, and a positive eye lens), which in concept is Galileo's 1609 telescope, turned around and used in reverse..

...The image size of reverse-Galilean finders is usually between 35-65% of full size.. 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 a comfortable viewing distance (15-30 feet), typically the image distance is set at 2-4 feet, ruling out bifocal wearers seeing the image sharply.. Consumers have had only this choice for so long that they have become inured to the problems of reverse-Galilean finders.

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:
• 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.

...The Albada finder is an upgraded reverse-Galilean finder.. An aluminized 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 Albada finder is used in only the most expensive point-and-shoot cameras; too expensive for single-use cameras.

...Consumers have not expected to find projected-frame finders in single-use cameras, having seen only minifying lens finders and simple open holes.. The patented Hines lensless viewfinder provides the projected frame of the expensive Albada finder, 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)

Hines Lensless 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:

HinesLab, Inc.

Glendale, California, USA

email: Steve@HinesLab.com

www.HinesLab.com/LenslessVF.html


...As a user approaches the camera, the frame on the back wall becomes out of focus and unobtrusive as the reflected frameline 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 (left).