In article <3316fe96.179281@news.taconic.net>, oblong@whatever.net says...
>On 27 Feb 1997 18:52:36 GMT, d_ruether@hotmail.com (Bob Neuman) wrote:

>|The Macro Vivitar 2X is actually quite good, and a bargain - especially
>|considering that the best use for 2X's may be for macro work (at small
>|stops). For tele work, the resultant aperture with the two-stop loss
>|plus the f11 lens optimum aperture for use with the short-lens type [...]

>Perhaps a clearer distinction should be made between the macro
>converter and the regular tele converter. From Vivitar's literature
>and elsewhere I get the impression that their tele converter is
>specifically designed for relatively long lenses and zooms. The macro
>converter explicitly is not. Its primary function is macro work in
>conjunction with a prime of moderate, fixed focal length, though with
>such a prime it can also be used to double the focal length for
>non-macro work as well.
>
>I used the macro converter to turn my 50/1.4 Nikkor into a 100/2.8
>that could focus to 1:1 for macro work and liked the results a great
>deal. The only problem was that the converter's aperture link kept
>breaking--probably because the Nikkor had been converted from pre-AI
>to AI and had too much internal friction for the Vivitar's linking
>system to handle.

I don't think there is really any difference in the Vivitar converters
between the macro-type and the standard 7-element version except for
the addition of the variable-length extension tube... And the 2X
Macro Converter is about equal in performance (and intended use) to the
Nikkor TC200/201 - they both are poor-to-good on all lenses they fit,
regardless of FL (they match some lenses fairly well, not others - and
both tend to best match lenses from about 28 to 85mm or so, giving
good results by about f5.6 and better results at f11 [though they can
be used succesfully on mis-matched lenses, if they are used well stopped
down). My point was that, since high-magnification macro requires small
stops for decent DOF anyway, that optimizes conditions for using the 2X converters for making sharp pictures - using them with teles (unless
the 2X converters are the long-lens type, and are used with the big ED
lenses) generally doesn't work very well, much as we might want it to.
BTW, I found also that the AI mechanism in the Vivitar converter does
tend to get sticky (well, heck, we must justify the cost of the
Nikkor somehow...!;-).
Hope This Helps