I've just bought a 7 element Teleplus 2X macro converter (for quite a silly
price I think - 19 UK pounds - and it looks multicoated). If nothing else it
is great fun! Together with a 50mm/3.5 macro (to quote a television engineer I
once knew) "it focusses from A****holes to Breakfast Time!" - all the way from
infinity to x1.7 magnification with a reasonable working distance. Putting my
100mm on bellows with the converter on the back gives up to 3.5x with serious
working distance. Since the helicoid on the converter moves the film plane
away from the object, ie in the opposite direction to the bellows and lens
helicoid, as a bonus you get a greater flexibility in focussing without having
to reposition your tripod. The downside is that you lose an extra stop of
light relative to using straight extension.
Actually, thinking about it, that last is only true for symmetrical lenses
(like the 50mm macro). According to my measurements the 100mm/2.8 lens has a
pupil magnification of about 0.7 and so a magnification of 3.5x using the
converter would lead to a loss of only about 5 stops compared to about 5.5
stops for the same magnification using extension alone.
David
Date: Tue, 29 Jan 2002 17:29:27 -0800
From: "Richard F. Man" <richard@xxxxxxxxxxxxxx>
Subject: [OM] 2X teelconverter vs....
I have a zuiko 180/2.8. Optically, how would it compare if I match it w/ a
2X teleconverter vs. say a 300/4.5? The teleconverted combination is
smaller and lighter no?
And if I have macro lens and extension tubes already, is there any
advantage of getting a 2X-macro vs. 2X w/o macro? I am specifically
thinking about the Vivitar version.
Thanks!
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