Actually, Clendon, macro lenses are optically optimized for close-up
pictures, whereas a regular lens is optimized for infinity or medium
distances. As you get closer, more aberrations show up using a regular
lens, and often there is curvature of field, so a flat subject may have the
corners out of focus. The 50/3.5 Zuiko macro has "floating elements" to
correct for this. As you focus, lens elements move with respect to each
other in order to correct these problems throughout its focusing range.
My question is, how much difference does it make? And where is the point
where if you want good image quality, you need to move away from using a
regular lens with either tubes or close-up lenses?
My Shipley book talks about all this, but has no pictorial examples of the
differences. He just says that a real macro lens is better, but only you
can judge what is acceptable image quality for your particular needs.
Based on what I've read, I believe the order from best to worst is (and
someone correct me if I'm wrong):
1. A real macro lens
2. A good normal lens with extension tubes (preferably not a high-speed
lens, ie. a 50/1.8 is better for macro than a 50/1.4 or 1.2)
3. Close-up lenses
4. A macro tele-extender
However, I'm not sure of the order of 3 and 4. Also, close-up lenses have
the advantage of less lens extension, therefore less light lost, therefore
easier focusing. Longer macro lenses give greater distance to the subject,
and therefore are easier to use in the field, but magnify camera shake and
are more expensive.
That's the theoretical stuff I've gleaned from reading. I'm looking for
people who have actually done it and can put the theory in proper perspective.
--Peter Klein
Seattle, WA
At 05:16 PM 10/29/2001 +0000, you wrote:
Date: Mon, 29 Oct 2001 08:16:39 -0800 (PST)
From: Clendon Gibson <bsandyman@xxxxxxxxx>
Subject: Re: [OM] Macro methods
I cannot really speak to the lenses you are asking
about.
You mentioned though that extension tubes and close up
lenses where stop-gap measures, which is not correct.
The macro lens you want to use instead is designed to
do what a regular lens with an extension tube does.
It's simply all built into one package.
In order to get the lens to focus closer, it has to be
moved farther from the film plane. That's physics.
The only reason to avoid close up lenses is if you are
woried about introducing distortions from having
another lens in front of the main lens. I have had
excellant results with close up lenses, but have not
done any blow-ups, so you may want to avoid these.
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