Understanding how to shoot macro with a reversed lens

So, what we're going to do in this movie may look an awful lot like a silly photographic hack.…But that's only because it's a silly photographic hack.…It is also, however, a completely valid, useful technique that you might already know about.…Let's start with the easy version.…If you have a prime lens -- that is, a lens with a single, fixed, focal length, -- get it out now.…I'm going to use this 50 mm lens.…Normally, of course, I would attach the lens to my camera like this.…So, I'm just going to go ahead and grab my shot with it.…A 50 mm lens on this camera is considered a normal lens. That means it's got roughly…the same field of view as the human eye. It's a pretty wide-angle field of view. And, what…I get with it is something like this. Hardly a macro shot.…

But now I'm going to take the lens off the camera. I'm going to turn it around, and hold…it up against my camera, completely covering the mirror chamber.…Now, being very careful not to drop the lens, I can frame up a shot.…Check this out, though.…