Professional-level cameras and consumer cameras have been getting closer in quality over the years. Gone are the days of the Instamatic. Point-and-shoot digital cameras are relatively sophisticated instruments that even pros tend to keep in their pockets for emergencies. However, the pros still use equipment generally out of the range of most consumers.
History
When photography first was invented in the mid-1800s, the camera equipment was too complex and expensive to be used by the average person. Matthew Brady took crews of assistants and photographers all over the country to photograph the American Civil War. After the war, getting one's photo taken became popular, but still required a professional. Photographers used bulky cameras with bellows on tripods and flash powder to capture the images of people from Abraham Lincoln to your great great grandfather. These cameras, still in use by some pros, are called view cameras. They shoot one photo on one sheet of film from 4-by-5 inches to 8-by-10 inches.
35mm
As film quality and camera lenses got better, it became possible to make smaller cameras. George Eastman offered the first cameras---Kodaks---to consumers that were boxes with a lens and a shutter. At the same time, Thomas Edison and others were making motion pictures and settled on standard 35mm film with sprocket holes on both sides. Oskar Barnack, who worked for Leica, created a standard 35mm camera that eventually became the rangefinder. This worked by having two viewing lenses set apart on the front of the camera. As you focus the lens, a mirror in one viewing lens turns until two images are superimposed to make one. That meant the camera was in focus. Leica then introduced interchangeable lenses. These Leicas became favorites of photographers around the world. The company still makes high-end film and digital cameras.
Medium Format
Some professional photographers wanted a compromise between the small, negative size of the 35mm camera and the large-sized view camera. Medium format cameras were designed to create a 2.25-by-2.25-inch negative. The primary producer of these cameras was and is Hasselblad. The camera that was the standard in fashion and architectural photography for decades was the Hasselblad 500C. This camera is totally modular. The basic camera body is a square with a lens mount on the front, a ground-glass screen on top, a shutter curtain and a wind-knob. To this you can add various film backs, changeable in mid-shoot, a variety of high-quality lenses---each with its own leaf shutter---and viewfinders from waist-level to prisms. Other camera manufacturers copied the format, which became the standard for wedding photographers.
Press and SLR Cameras
In the middle part of the 20th century, the press camera came into vogue, particularly with newspaper photographers. These square and bulky cameras produced large negatives, had a flash bulb unit attached and took little if any focusing. By producing the big negative in a hand-held camera, newspapers could have large, sharp photos without the need to set up bulky equipment. These were largely supplanted when Pentax introduced the pentaprism in the 1950s. The pentaprism allowed the creation of the single-lens reflex 35mm cameras because, using a 45-degree flip-up mirror, you could see the image through the same lens that was taking the photo. This meant you could use telephoto lenses longer than the then-standard 135mm type. The 35mm SLR became the standard for most pros, especially those who needed to shoot fast.
Digital
Today, most professional photographers use either 35mm-style digital cameras from Nikon, Canon or Pentax or they have remained with medium-format. The 35mm-style digital camera still doesn't have the quality of film, but it is fast and handles many of the aspects of shooting such as focus, aperture and shutter speed settings. These type cameras are used by photographers from newspapers to weddings to glamour. The medium-format digital camera, particularly the Hasselblad, has high resolution coupled with top-quality lenses. Photographers use them generally for magazine shoots and other situations where the best photo quality is needed.
Tags: digital cameras, 35mm camera, 35mm film, 35mm-style digital, became standard