Early forms of holography and photography have a lot in common, as they are based on the same basic principles. Both holography and photography record images on chemically-treated film, often containing a silver halide coating. They are also both processes that utilize the reflected light from objects, and this directly affects the resolution of an image depending on how close the recording device is to the object image being captured. As well, both holography and photography equipment started out as basic and expensive technology that has become more portable with advances in microelectronics.
Three-dimensional images captured in holography utilize a laser beam that is split into two beams. One-half of the beam images the object being recorded, and this laser light reflects back to the recording film. The other half of the laser beam is channeled through a lens and reflected off of a mirror, impacting with the film and interacting with the imaging half of the laser beam in the process. This causes two versions of the image to be recorded on the film from slightly different angles simultaneously, giving the image a three-dimensional (3D) appearance when viewed from various angles. Since holograms are a unique type of double exposure, holography and photography are similar in that a holographic recorder is essentially a form of two cameras operating on one section of film.
Advances in holography and photography technologies have begun to drive the processes through which they function apart as of 2011. Digital cameras for photography no longer require the use of film, so this makes them different from holography that largely still does. Holographic images, however, are now recorded on different mediums, from specialized glasses to plastics that go beyond the standard silver halide film technique. Some modern holographic systems also utilize lasers in three colors of red, blue, and green to generate true color 3D images, and, often, these lasers must be continually on for the image to be generated off of a reflective medium.
Improvements in photographic technology have made many types of standard cameras far less expensive than early models with improved features. By contrast, advanced holographic systems that generate true color 3D images are more complex, involving multiple laser systems, and much more expensive that primitive monochromatic early hologram recorders. As hologram technology progresses, projections are that it will become more commonplace and prices will fall, though such systems are likely to lag behind the widespread use and development of digital cameras.