Can someone explain macro?

[Jonathan Gingerich]

Okay, off-hand it would seem that the two characteristics of a macro
lens would be what is the smallest full field it can capture, and how
much depth of field can it provide. Yet description after description
emphasizes how close the camera can be placed to the subject.
Does distance have any correlation to field or DOF? Does it have some
affect on the "angle" of the image that I'm missing? Is there any good
site for macro specifications of competing camera models?

Thanks,
Jon.

[jaykinghorn]

Jon,
The defining characteristic of a macro lens for DSLR type lenses is the ability to focus at very close distances (subject to lens). Normal lenses are not able to focus any closer than 1-2 meters, but macro lenses are able to focus on subjects a few inches from the lens.

Depth of field does decrease as the distance from subject to lens decreases. Your aperature setting will have an effect on the overall depth of field as well.

I would look on the manufacturer's websites for the technical specifications of macro lenses.

Jay Kinghorn
RGB Imaging

[Jonathan Gingerich]

So is the closeness simply a working convenience? Wouldn't it be
better to have focal length of about a foot or so?

[John_Reed]

So is the closeness simply a working convenience? Wouldn't it be
better to have focal length of about a foot or so?Strictly speaking, I don't think that "closeup" is the same as "Macro." I think that "Macro" means capturing an image which is at least the same size or larger than the subject on the "film." From 35mm film days (which are still with us :o), this would mean if you shot a subject of 24mm X 36mm, it would "spill over" on your 35mm camera's film image. How one makes the transition to digital imagery while maintaining that definition isn't clear to me. Here's a photo that I think would qualify as a "macro:"
http://john-reed.smugmug.com/photos/4223420-L.jpg
It was taken with a Panasonic FZ1 camera with a Nikon 6T +3 diopter magnifier on the front. At full telephoto on the FZ1, the distance from the camera to the Bee was ~10 inches, if you want to call that "focal length." As to whether it's a "Macro" or not, if you think of the image as the full frame of a slide, 24mm high, (about an inch) I think the Bee is about life size on that photo.