What is a DSLR and is it different from SLR or Film SLR?

 SLR and DSLR are very similar or we can even say same in functionality. The only major difference between them is the medium on which the light is captured. The film SLR uses films as the light sensitive medium and the digital SLRs or DSLRs have digital sensors to capture the light. Other differences include the massive menu systems and the screen provided to review the images on a DSLR. Film SLRS have very simple menu systems and mostly mechanical controls using knobs and dials. After digital revolution came to being lots of functions are being controlled using menu systems and some of them very typical to the digital photography which were not required for film camera.  But both these cameras work using the same philosophy.