We’ve compiled a list of those to help you make the decision that’s best for your photography needs. What is a DSLR Camera? DSLRs use the same design as the 35mm film cameras from the past. A mirror inside the camera body reflects the light coming in through the lens up to a prism, and into the viewfinder for you to preview your shot. When you press the shutter button, the mirror flips up, a shutter opens and the light falls onto the image sensor, which captures the final image. One example of a DSLR camera is the from Beachcamera.com. Nikon D3400 What is a Mirrorless Camera?