In article <5b0k47$5f4@cello.hpl.hp.com>, jacobson@cello.hpl.hp.com says...
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>>4. I noticed that some are specifically labelled "macro". If you
>>currently have a lens with macro capability and want to use a
>>teleconverter does the teleconverter have to be macro as well? Also, (I
>>doubt this but I'll ask it anyway) If you have a normal lens will adding
>>a macro teleconverter make it a macro lens? I doubt this since adding a
>>teleconverter would not affect the ability of the lens to close-focus.

>I have no good idea why they are labelled macro. If anyone knows,
>please post. An ordinary teleconverter just expands the central
>portion. If it is a 2X converer and you could image 1:6 with your
>regular lens, you can get get to 1:3. Maybe that is what they mean,
>but that would be true of any teleconverter. Maybe they mean that it
>is a combination teleconverter and extension tube. I don't know.

Vivitar (maybe others) marketed (still does?) a good 7-element 2X
converter with an added front variable extension tube (0<->c.25mm)
extension that would effectively turn normal lenses into macro
lenses, and provide closer than normal focus with all lenses.
When used with the lens at smaller stops, image quality can be
excellent.
Hope This Helps