It differs from other cameras in one major
way....what you see through the viewfinder on an SLR camera is actually what you will be
photographing, whereas on most normal cameras, the viewfinder is not exact.
This is due to the way the cameras are set up. An
slr camera is set up with a mirror that internally takes the light (the image) coming in through
the lens, and forwards it to the viewfinder.
This set-up allows you to see, with the finest
clarity, exactly what you will be taking a picture of.
Other cameras have two light paths; one for the viewfinder, and
one for the actual picture taking action. The problem with these cameras is that they do not represent a true match
between the viewfinder and the lens. They will be a bit off, especially on close-ups. It might not seem like it
would make a big difference, but it does in many situations.
Slr cameras take this difference away by making the view screen
precise, which can really help you to catch action on your camera that you might not be able to capture correctly
with a regular viewfinder.
Nowadays, digital cameras do the same thing as an slr camera,
though an slr camera takes pictures faster than a digital, which is why a lot of serious and/or professional
photographers still use them.
They used to be one of the most advanced camera systems on the
market until the advent of the digital camera with an lcd view screen. These screens make it easy to see what you
will be photographing, and it is hard to beat their inexpensive price. SLR cameras are still awesome though....so
if you are into photography, try one out sometime. And, if you're getting an SLR camera, be sure to
check out the SLR
camera cases!