History of SLR Cameras

The single lens reflex (SLR) uses an automatic moving mirror system which permits the photographer to see exactly what will be captured by the film or digital imaging system and is most folks' idea of a serious camera. SLR means that the same lens is being used for viewing and as well as taking pictures. A mirror in the body directs the light from the lens right up into a prism for viewing, and then flips up out of the way just before an exposure is made.

The standard photojournalist's Nikon from the 1960s or 1970s was an SLR with a roll of 35mm film behind its mirror. When the mirror came up, the light passed through to the shutter, which opened to expose one frame of the film for perhaps 1/60th of a second. Nikon D80 looks very similar to it and works in almost the same way. The only difference being that instead of a piece of film behind the shutter there is an electronic sensor.

With the digital SLR you have fairly good idea of what you're going to capture by looking right through the viewfinder. When you press the shutter release, the camera captures the image instantly. If you need to zoom or focus manually there are large rings that you can operate quickly by just a feel. If you come across a beautifully-lit scene you can capture that beauty instead of using an on-camera flash to blast everything with harsh white light. If you need to make a specialized photo, you just need to buy or rent a specialized lens and attach it to your camera.
The mirror and the optical viewfinder are what that enables a photographer to frame images more quickly and accurately than with a point-and-shoot camera. Regardless of what lens or filters you have attached to the camera you will see what the sensor will see. The typical SLR camera viewfinder offers additional information underneath the image, including all the most important camera settings.

A point-and-shoot compact camera can offer reasonably good image quality, but a SLR, which usually looks a lot like an old standard 35mm film camera and may use the same lenses, offers the following advantages: (1) accurate, large, and bright optical viewfinder, (2) fast operation and large controls, (3) excellent image quality in low "available" light situations when it is necessary to use higher ISO speeds, (4) interchangeable lenses. SLR may offer the same number of megapixels, individual image elements, as a high-end point-and-shoot; however, not all pixels are created equal. Resolution is an important factor if you intend to make large prints but dynamic range, the ability to capture detail within bright highlights and dark shadows, is more critical in many situations. To accomplish the task, large sensors are used by SLRs’.

The SLR is much larger and heavier than the traditional point-and-shoot camera, and if you are leaving the house to socialize and want a camera to keep in your pocket just in case an interesting photo presents itself, the SLR will seem cumbersome. But if you are heading out specifically with a photographic project in mind you will appreciate how the SLR and its controls fit into your hands.