I don't like posting URL's with mainly non-English text-content, but 
this one is quite interesting....

http://www.weihenstephan.org/~joachenk/makrozoom.html

(German)

The writer starts by describing the Zeiss Tessovar macro-zoom as the
only true macro-zoom (ignoring both the Minolta 3-1x and Canon 5-1x
micro-lenses IMO), but he is then confronted with the results of a
normal EOS-zoom (28-135), reverse-mounted, through a Novoflex
reverse-adapter, being optically on par with results from Zeiss
Luminar lenses (considered state of the art in photo-micro land).
It is optically explained by the fact that the big front lens of the 
zoom, now facing the camera, is only used in the center, where even a 
lousy engineer can do a decent job.
This is similar to the theory of why a TS-E 24/3.5 is still so good 
when being combined with a 2x converter....

Interesting side-note: the 28-135 offers a continous
focus/magnification range of infinity(!!) at 135mm to 3:1 at 28mm
(nearly touching the glass, the downside of a small focal 
length, especially since the diameter of the (then) front lens is 
much larger than say a Luminar).

More photo-micro data, including the Tessovar, can be found on my 
homepage:

http://www.a1.nl/phomepag/markerink/mainpage.htm

(or /microlen.htm & /tessovar.htm directly)

















--                 
Bye,

Willem-Jan Markerink

      The desire to understand 
is sometimes far less intelligent than
     the inability to understand

<[EMAIL PROTECTED]>
[note: 'a-one' & 'en-el'!]
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