1.) The earlier commercial camera was based on the Camera Obscura which is a portable room that was made by the Arabians in the 10th century.
In the 18th century, this model became more reduced and more portable and had a lens attached to the camera for making an image sharpener for drawing. Lucida of the 19th C.E was used for travel and used as a tracing device.
Thus today camera has evolved from the earlier models the camera to a light sand captivating fragile tool.
2.) I'm going to go with Henri Cartier-Bresson and Carrie Mae Weems.
French photographer, Henri Cartier-Bresson, was the father of the "decisive moment" and a master of creating clean, compelling compositions with action and movement. The idea behind the decisive moment is that there is a fleeting fraction of a second in any action or scene that can best capture the essence of it in a photograph. He began work in the mid-1900s and passed away in 2004. There is also a famous quote attributed to him that is one of my favorites to share with new students. He said, "Your first 10,000 photographs are your worst." That can sound discouraging, but really, I just think of it as driving home the importance of taking way more photos than you need to get to your golden images!
Black American photographer, Carrie Mae Weems has been an amazing influence on artists and offered compelling commentary on race, gender, art, and politics in her pioneering work. She began her published work in the 1980s and continues to exhibit today. I had the honor of attending a talk she gave a couple of years ago at the University of North Carolina at Chapel Hill.
I also love the work of William Eggleston, Cindy Sherman, Gordon Parks, and Diane Arbus.
Regarding the changing uses of photography over the years, I would first mention that photography was not originally accepted as an art form worthy of museum exhibitions until really the early 1900s. Alfred Stieglitz was one of the early photography-as-art pioneers. Later, color photography was not seen as art and was considered vulgar by purists. William Eggleston was one of the photographers who helped to shake that up. We've continued to use photography as a document, and photojournalism remains crucial today. The photographers employed by the Farm Security Administration during the dust bowl of the 30s in the U.S. like Dorothea Lange and Walker Evans, as well as Gordon Parks, come to mind as documentary photography greats. Another photography great, Annie Liebowitz, makes me think of the lines between advertising and fine art has become increasingly blurred.
3.) Nicéphore Niépce is the father of photography. In around 1816. Niépce became interested in the new technique of lithography and began to explore ways of using light-sensitive materials to produce images directly onto the printing plate or stone. The first successful photo was taken in 1826. Niépce used his heliography process to capture the first photograph but was soon overshadowed by the invention of the daguerreotype. The place of the shot was taken in Niépce's estate in Burgundy.
4.) Technically, photography has changed in that digital imaging has matured and advanced image-making creativeness possibilities and quality beyond what most people could conceive 20 years ago.
Professionally, the advent of easy-to-use digital cameras and unlimited shooting for essentially free has basically destroyed the professional photographers’ ability to charge a relatively living wage for workers. A few still command decent prices, but digitization has created commoditization, which always equals pricing deterioration.
The way we view images has changed from open and inviting prints on refrigerators, desks, and walls; to email snapshots that must be opened to participate and that we invest 5 seconds in viewing before terminating them.
As with every industry that has been impacted by digitization, great disruption has occurred. Sometimes for the better as in expanding the top one percent of creatives and in potential image quality. Most times diluting image quality by diluting the talent pool with mediocre uncommitted practitioners. (Like adding water to good wine, the more water the less desirable the wine. Taste, personality, and care are wasted by the dilution.)
Socially, the so-called democratization of photography through digital has diluted the commitment to quality image-making. Many people are just happy to get an image, even when they are beyond mediocre.