The DSLR is the digital version of the 35 mm film SLR which itself was a big improvement over rangefinder cameras when they came out. Before SLRs, 35mm and medium format photographers did not see the exact same view that their film saw. There was a slight shift in perspective, similar to the difference you see between your left and right eyes. The viewfinder saw one perspective and the lens saw a different one. When mirrors were added the viewfinder saw the same view as the film,. It works like a periscope.
it wasn’t long before the SLR became the standard for high quality and professional photography.
When digital cameras came along, SLRs were simply modified. Film was replaced by a light sensitive plate and more electronics added to process the light data. (And a “D” was added to the acronym.)
At the same time DSLRs were being developed, digital point and shoots were also being made. The acronym DPS never really caught on, though.
Point and shoots offer an electronic, near-real time view on their LCD screens instead of the actual scene viewed through glass like with DSLRs. Some even have LCDs built into view finders.
Point and shoots are handy and less expensive than DSLRs but they do not typically measure up in quality. The sensors are generally smaller and they don’t perform as well in many situations. But that is changing.
At some point manufacturers started building point and shoots with interchangeable lenses and began calling them mirrorless cameras. Things have improved rapidly and mirrorless cameras are beginning to catch up with DSLRs. They are smaller, lighter, quieter and easier to handle than their bulky cousins. The sensors are getting larger and lenses getting faster. Many pros and advanced amateurs use them regularly with great results.
While we probably won’t see DSLR disappear soon, chances are they will slowly start to become obsolete as fully electronic cameras begin to dominate. A high functioning mirrorless camera is easier to handle and can allow the photographer to concentrate on the image rather than the camera. Like anything it may take getting used to, but so did SLRs when they first came out. With new technology it is always just a matter of adapting.
As I learn more and more I’m guessing that my next camera will probably be a high end mirrorless camera and I am looking forward to it.