An SLR camera offers the most power and flexibility.
SLR means Single Lens Reflex. The photographer is actually looking through the lens when he composes his shot; then when he clicks the shutter, the reflex of the camera is that a mirror pops out of the way as the shutter opens, exposing the digital sensor.
The Single in Single Lens Reflex
The single in single lens reflex comes from the fact that there is a single path for the view finder and the exposure. This is different from older or more basic cameras that use a dual path for these two functions. In those cameras, the viewfinder is parallel to the lens but separate.
This has two disadvantages. First, as the angle of the shot and the distance to the subject changes, the perspective will be slightly different, so what you see may not be what you get. Second, a separate viewfinder usually can't take advantage of a zoom lens' changing magnification.
The Lens in SLR
The lens part of SLR refers to the fact that the user is actually looking through the lens as he composes the shot. This means that what you see is exactly the same thing that the digital sensor will see. The angle, perspective and zoom magnification will be the same in the viewfinder as what ends up in the image.
The Reflex in SLR
Finally, the reflex part of SLR refers to the action, or "reflex" of the camera when the photographer clicks the shutter. While looking through the viewfinder, the user is actually looking into two mirrors that reflect the view shown through the lens back through the viewfinder. When they click the shutter button, not only does the shutter open for the length of time set in the shutter-speed, but the mirror between the lens and the sensor flips up out of the way, allowing light to expose the image.
Other Advantages
The other main advantage of SLR cameras, although it isn't a part of the SLR technology is that almost all SLR cameras allow the user to change lenses. Allowing the photographer to choose between an array of magnifications, speeds, qualities, and other technical differences in modern lenses is what truly sets the SLR camera apart in terms of power and flexibility.
Disadvantages
There are two main disadvantages to the SLR digital camera. The first is initial cost. Even a basic body and one or two budget lenses will cost more than most point-and-shoot cameras.
The second is the learning curve. This applies not only to the time it takes to learn all the controls and functions of the SLR camera. A point-and-shoot camera does a lot of the processing and finishing of the image. With a digital SLR camera, this work is left up to the photographer to handle.
Tags: actually looking, looking through, through lens, actually looking through, clicks shutter
