Definining DSLR camera

     In the most literal sense, a DSLR camera is a digital single lense reflex camera. Inside the camera body is a mirror that reflects the light coming from the lens up[ into an optical viewfinder, by way of either a prism (in higher-end DSLRs) or a seris of additional mirrors (usally in lowe-end models). This is how you can see what you're shooting, right thought the lens, and is where the terms "
reflex" comes from freferring to mirrors' reflection.

When the shutter is pressed, that mirror flips up out of the way, the shutter slides open, and light comming from the lens takes a straigt shot the imaging sensor where a photograph is made. 

The advantage of this desing, compared to that of mirrorless or point and shoot camera, tis that you can see, in real-tme, the exact scene you