Digital SLR (single lens reflex) is a form of a digital camera. Digital SLR's are used by professional and by photo enthusiasts. The cameras can be fixed or interchangeable lens. The interchangeable lens feature is what appeals to both professional photographers and photo enthusiasts, they both like being able to control how much zoom the camera has by changing lens's.

 

Here is how a digital SLR camera works:

1. For viewing purposes, the mirror reflects the light coming through the attached lens upwards at a 90 degree angle.

2. It is then reflected twice by the pentaprism, rectifying it for the photographer's eye.

3. During exposure, the mirror assembly swings upward, the aperture narrows (if stopped down, or set smaller than wide open), and a shutter opens, allowing the lens to project light onto the image sensor.

4. A second shutter then covers the sensor, ending the exposure, and the mirror lowers while the shutter resets.

5. The period that the mirror is flipped up is referred to as "viewfinder blackout".

6. A fast-acting mirror and shutter is preferred so as to not delay an action photo.