RE: horsetail close-ups

Larry,

I haven't tried yet to couple a lens reversely onto another one. But I just
tried pressing two lenses together and found that a single reversed lens
(28mm) gives a clearer picture and higher magnification than 28+R50, 50+R50,
or 80+R50.

I assume with "macro lens" you mean the telelens type with a macro position,
not the premount filter lens. I have several reasons not to use such a macro
lens for plants (animals are a different story!). First they tend to be heavy
and quality optics are awfully expensive. But they can be easily mimic-ed by
an ordinary tele-lens with an additional extension tube element. But even then
the working distance is often too large to be convenient. Furthermore, my
plants are slow movers, so as long as nobody bumps my desk, the shutter can
remain open for hours if necessary. Just as long I got enough light to focus.

With my present set-up however, I can use old-fashioned, cheap but high
quality East-German optics that are readily available on the 2nd hand marked.
Moreover, the extension tubes confine the light to the central parts of the
lens, where distortions and aberrations are the least. It's not yet optimized,
but remember this was only my first try.

Wim

-----Original Message-----
From:	owner-ferns@hort.net on behalf of Larry Shone
Sent:	Mon 5/23/2005 3:06 PM
To:	ferns@hort.net
Cc:
Subject:	Re: [ferns] horsetail close-ups
Neat set up Wim, sound like you got quite a magnification range(set of 3
extension tubes plus a 50mm should give at least 2.5 X)
Do you not have a macro lens or a lens of between 80 and 135mm focal
length-you would be better to reverse the 50 onto that, then you wouldnt
suffer any light loss which is inevitable when using extension tubes.
(I reverse a 50 onto my 100 macro on my Canon EOS 300 which gives 2X
lifesize)

Regards
Larry
----- Original Message -----
From: "Winter, Wim de" <Wim.dewinter@wur.nl>
To: <ferns@hort.net>
Sent: Monday, May 23, 2005 11:26 AM
Subject: RE: [ferns] horsetail close-ups


> It's a Canon 300D, aka digital Rebel. I mounted it on a dismantled
binocular microscope, with 3 EOS extension tubes, an eos-M42 adaptor ring, 3
M42 extension tubes, a reverse ring and an ancient Practica 50mm lens
mounted upside down.

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