With the gradual recognition and acceptance of digital cameras, the market of digital cameras is also expanding. In order to cut off this big cake, digital camera manufacturers continue to develop new technologies or quickly apply existing technologies to the digital camera field to maintain and enhance their position in the digital camera field. Sony used holographic laser autofocus assist in the focusing mode of DSC-F707. In other words, holographic technology has been applied to the field of photography, so what is holographic technology? What's the difference between holographic photography and traditional photography?
Hologram was put forward by Gabor in 1948 to improve the imaging quality of electron microscope, and its significance lies in complete recording. Dennis gabor's experiment solved the basic problem in the invention of holography, that is, the recording and reconstruction of wavefront. However, due to the lack of bright coherent light source (laser) at that time, the imaging quality of hologram was poor. With the appearance of 1962 laser, Lise and Upatnieks introduced the concept of carrier frequency to Gabor holography and invented off-axis holography, which effectively overcame the main problem of poor hologram imaging quality at that time-twins, and the display of three-dimensional objects became the focus of holographic research at that time, but this imaging science far exceeded the economic development at that time, and the cost of making and observing such holograms was very expensive. 1969, Benton invented rainbow holography, which set off a new climax of holographic stereoscopic display characterized by white light display. Rainbow hologram is a kind of plane hologram that can display white light. Compared with Denisyuk's reflection hologram, it can not only observe bright stereoscopic images under ordinary incandescent lamps, but also has the advantages of simple hologram processing technology and easy replication.
The application of holographic technology in photography is far superior to ordinary photography. Ordinary photography is based on the principle of lens imaging, which projects a three-dimensional scene onto a flat photosensitive floor to form a light intensity distribution. The recorded photos have no stereoscopic effect, because the images obtained from the photos are the same from all angles. Holography reproduces the object light wave accurately. When we "look" at the light wave of this object, we can observe different sides of the reproduced stereoscopic image from all angles, just like seeing a real object with depth of field and parallax. If we shoot two Mercedes-Benz cars side by side, then when we change the observation direction, the blocked part of the latter car will be exposed. No wonder people are excited about the hologram taken by a Mercedes-Benz car in the exhibition: "It's amazing to see the reappearance of the car, as if you can get on the Mercedes-Benz as soon as you pull the door!" A hologram is equivalent to many ordinary photos, shot from multiple angles and focused. In this sense, the information content of a hologram is equivalent to 100 or 1000 ordinary photos. When you look at the hologram surface with a high-power microscope, you can see complex stripes, but you can't see the image of the object at all. These fringes are formed by the interference between the object light wave emitted by the laser irradiation object and the standard light wave (reference light wave), and are recorded on the plane photosensitive substrate, that is, the object light wave is "frozen" by the coding method. Once the illumination light wave similar to the reference light wave is irradiated, the imaging light wave will be diffracted, just like the original light wave is released again. So the principle of holography can be expressed in eight words: "interference recording, diffraction reproduction".
Knowing this technology, we can use holographic technology in a wide range of fields and shoot some precious cultural relics with this technology. During the exhibition, the cultural relics can be truly reproduced in three dimensions for visitors to enjoy, while the original objects are properly preserved to prevent theft. Large holograms can not only display cars, satellites and various three-dimensional advertisements, but also reproduce portraits and wedding anniversary photos through pulse holography. Small holograms can be worn around the neck to form beautiful decorations, which can reproduce people's favorite animals, colorful flowers and butterflies. The rapid development of embossed rainbow holograms can not only become lifelike cartoons, greeting cards and three-dimensional stamps, but also appear as anti-counterfeiting marks on trademarks, ID cards, bank credit cards and even banknotes. Holographic stereo photo decorated on books and holographic rainbow shining on gift packaging make people realize the new leap of printing technology and packaging technology in 2 1 century. Molded holographic logo, because of its three-dimensional layering, rainbow effect changing with observation angle, ever-changing anti-counterfeiting logo, and the close combination with other high-tech anti-counterfeiting means, has pushed the anti-counterfeiting technology in the new century to a new brilliant peak.