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Re: [OM] Macro Reversing

Subject: Re: [OM] Macro Reversing
From: Dr Peter Gilbert <peterg@xxxxxxxxxxxxx>
Date: Fri, 15 May 1998 16:21:21 +1000
There are two types of reversing rings that I am aware of.

The first has a filter thread on one side and a mount (ie OM bayonet) on
the other. With this, you screw the ring onto the front of the lens you are
reversing, then bayonet the lens backwards onto the camera (or bellows or
ext tube etc) that you are using.

The second type is simply a male-male double sided (glass-less) filter
thread, where you put a lens onto the camera body (or bellows or ext tube),
screw in the male-to-male  filter adaptor, and then screw another lens onto
the front of that, such that the two lenses are front to front, separated
by the male to maler adaptor. It's a good idea to stick to two lenses with
the same filter size eg 55mm - 55mm  or 49mm - 49mm. Remember this when you
buy your adaptor!!

 I don't have my notes with me at the moment, but from memory, you put the
longest focal length lens onto the camera directly, and then a smaller
focal length lens backwards on the front of it, and the magnification you
get (theoretically) is equal to the ratio of their focal lengths.

eg      200mm on camera, 50mm reversed  => mag is 4.0           ie 6mm x 9mm
        200mm on camera, 100mm reversed  => mag is 2.0                  ie
12mm x 18mm
        100mm on camera, 35mm reversed  => mag is approx 3.0    ie 8mm x 12mm

you get the idea

this is supposed to give better quality than close-up diopter lenses (hey -
you've got a multi-element zuiko diopter now!), but it is cumbersome and
vignetting appears to be by trial and error. I would suggest if you want to
try this method that you get a good reversing male-to-male adaptor (metal
if possible) - if it breaks, the reversed lens goes for a swan dive. I'd
definitely keep away from sticking tape!!! The other concern is that the
back end of your reversed lens is sticking out unprotected (you can't
attach a filter or a lens hood to the back of most standard/wide angle
lenses) so be careful. It is really a studio type setup I think.

I can't remember details, but I think the lens combo used also affects
working distance for any given magnification. ie a 100mm on a 200mm will
give more room than a 50mm on a 100mm even though they both achieve 2.0x
magnification. Again, best advice is to experiment, use slide film, and
scrupulouly record which frames you exposed with which combination of
lenses and apertures.  I recall that aperture played more of a role than
just determining DOF and correct exposure - it can increase or decrease
vignetting too.

I played around with this kind of setup when I started macro photog, but am
fortunate enough to now own some nice zuiko macro lenses and the 65-116
tube which is just the most brilliant device (in the field or in the
studio). Teamed with OTF TTL flash and my OM-4Ti  it is a joy to use. I
have the 90mm f2 and 50mm f2 macros for field work, and the 80mm f4 (with
2:1) lens for studio work. I am eagerly awaiting my new baby - a new 38mm
F2.8 zuiko macro which I ordered yesterday.

Having said that, I really enjoyed experimenting with different lens
combinations etc back in the early days with a manual flash and my OM-1n.
Ahhh fond memories indeed, and a good apprenticeship I think.....

Note that the higher the magnification (regardless of how you achieve it)
you decrease depth of field dramatically. Anything over lifesize and you
can literally measure DOF in millimetres or fractions therof. A macro
focussing rail and a damn good tripod and head should be on your shopping
list if you are going to do greater than lifesize photos on a regular basis.

Hope this helps - enjoy experimenting!

peter

>Hello All Olypus Macro shooters.
>
>
>
>Has anyone done much work with using a reversing ring to produce a macro
>lens out of two zuikos.   A while ago I did some photos using sticky tape to
>join the lenses together.   Worked quite well however I ran into a couple of
>problems
>
>       Depending on the lense combination used I got a lot of vignetting
>
>       The depth of field obtained was too small.
>
>
>I did find that of the photos that did work correctly I got a much better
>results than using the Hoya close up filter/lenses I have.
>
>I have the following lenses and would like to know which successful lense
>combinations and f/stops have you been able to use to avoid vignetting and
>obtain a reasonable depth of field.
>
>28 f2.8
>35 f2.8
>50 f1.8
>100 f2.8
>135 f2.8
>200 f4
>400 f5.6
>
>p.s  I just bought a second hand reversing ring for $5 AUD.  It allows a
>49mm filter to be backed onto a 55mm filter.....
>
>
>
>
>Stuart Goggin
>
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