Know the number Shutter Count it is important for those who have a digital camera because by knowing how much Shutter Count from your camera then you will also know the age of your camera.
The shutter count is the number of pictures that a camera has already taken. Also known as actuations. The number is important with used cameras because the shutter blades are delicate mechanical parts, subject to wear & tear.  More
DSLR or SLR (Digital Single-lens Reflex Camera) technology is a combination of DSLR cameras or digital SLR cameras, this turns out to be made to replace film of photography camera. Camera SLR & DSLR cameras have features that are very advanced are:
Video recording with HD resolution and features contrast detection and auto-focus
Dedicated keys for both sensor ISO image, if necessary. More