A series of articles counting down to Asahi (Pentax) 100th Anniversary
Pentax Forums will be presenting a series of articles on the evolution of the Single Lens Reflex (SLR) Camera from obscurity to its present iteration known as the DSLR and particularly Pentax's present-day flagship, the K-1 Mark II. The series will continue through November, 2019 when we celebrate the 100th Anniversary of the ASAHI Optical Co., the founders of the Pentax Camera.
Origins of the Single Reflex Camera (SLR)
Many of you are familiar with the SLR as one's every day camera, yet many of you are likewise unaware that the origins of the Pentax SLR (and for that matter, all makes) actually has its origins in the 4th Century BC (circa 330 BC) as a means to protect one's eye from damage in viewing a solar eclipse.
Aristotle and his contemporaries described a metal plate punched with small holes through it and then held up to the sun which would then project a corresponding image onto the ground. In essence, the foundation of photography is based upon this simple optical principle.
In the 11th century, a remedial version of a 'camera obscura' (Latin for 'dark chamber') was developed. A room or a box lit only by a single small hole or window that admitted daylight would create a shadow image of the outside world on the opposite wall. Later in the 13th Century, a medieval inventor named Roger Bacon used the 'camera obscura' technique with mirrors to project optical sites and illusions by projecting sun visions on an opposing wall
Camera obscura concept
However, it was not until the Renaissance period that brought more rapid development of the use of mirrors in creating images. Leonardo Da Vinci is credited with using a camera obscura to draw but that claim has been debunked. In fact, Da Vinci built a small camera obscura to test his theories of the human eye and depth perception, but without a lens, Da Vinci's camera obscura was not effective.