What is the difference between Oakley A Frame and O Frame?

Whats the difference between a full frame lens and none full frame?

• I wanted to know the difference between a full frame lens and none full frame. and how can you tell which one is which when buying one?

• Answer:

  The generic answer to a very generic question is: not much. Lenses provide an "image circle" on the sensor/film. A lens designed for full frame has an image circle that covers film or sensor that is 24x36mm in size. "Non full frame" lenses are designed so that the image circle covers the area of the smaller sensors used in the majority of digital SLR cameras, approximately 18x24mm in size. Other than that... each maker has a specific designation for lenses designed for the smaller sensors. Canon uses EF-S, Nikon calls them DX, Sony calls them DT, Sigma uses DC, Tamron uses DiII. The only one that doesn't is Olympus, as all of their digital cameras use the same lenses, they only have 1 sensor size. To make it even more interesting, 1 maker's non-full frame lenses will actually break a full frame camera if you mount one. Others allow you to use the lenses, and automatically crop the full frame image to use the central area of the image circle.