I didn't make a very good job of explaining in words the result of using a
CCTV lens stacked on a Zuiko 20/3.5, so perhaps a couple of example images
will do a better job (even if the subject is just a ruler, marked in
centimeters/millimeters). The files are 150-200k jpgs.
www.hemy.me.uk/Miscellany/50+25tube.jpg was taken with a Zuiko 50/3.5 with
25mm extension tube at 1:1, lens at f/22.
www.hemy.me.uk/Miscellany/Tandem20+4.jpg was taken with a Zuiko 20/3.5 with
150mm of bellows extension, lens at f/3.5, coupled to a 4mm CCTV lens which
was mounted to the Zuiko using a custom engineered adaptor. OK, I fitted
the CCTV lens into a 35mm film canister with a hole in the base to clear the
Zuiko aperture ring, and clamped the assembly to the Zuiko body using a
collar (the 'precision' collar was made from gummed paper wrapped around
another 35mm film canister and left to dry).
The exposure tiume for both images was 1 second, and in each case the ruler
was placed against the front edge of the taking lens (the 50mm or the 4mm).
Thus the perspective is slightly different, since the 50mm is much wider
tthan the 4mm. Also, the repro ratio may be very slightly different.
I suspect the result shows two things:
The Zuiko 50/3.5 can produce bitingly sharp images over a limited range -
less than 1cm
The tandem arrangement cannot match the resolution of the 50/3.5, but
produces its best result over a wider image field - perhaps 2cm, but with
apparently much shallower fall-off.
My impression is that the optically-inferior results are pictorially
superior - any other views?
--
Piers
-----Original Message-----
From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On Behalf
Of Chuck Norcutt
Sent: 11 September 2005 18:57
To: olympus@xxxxxxxxxx
Subject: [OM] Re: OM macro lenses?
--snip
Wanna try again :-)
Chuck Norcutt
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