T0M722

DSLR stands for "Digital Single Lens Reflex". Basically what it does is there is a penta-prism above the lens, hence the big bulge. This penta-prism reflects the light coming in to your eye (Its a little hard to show here) after its reflected 90degrees upwards by the mirror. This gives you a "what you see is what you get" image. You don't see a LCD screen inside the viewfinder that "shows" you what you potentially take a picture of. You see the image that the image sensor's gonna pick up. This allows you to focus better and compose your pictures better. Because no matter how high the resolution in the LCD screen your eyes peek at in the viewfinder, its not gonna be as clear or precise as seeing "real light". Anyway back to the reflecting of light, when you push the shutter down, the mirror flips up for a duration that you set (Shutter speed), light hit the sensor, which "takes the picture", after which, the mirror (shutter) flips back down, stopping any light from hitting the sensor.