e - Ken Gilbert

Macro Focus stacking
then take the pictures by gradually
racking the lens backwards,
depending on the increments, until
the fly becomes out of focus again at the
front end,’ he explains. David always uses
manual focus, because when working this
close your autofocus can get easily confused
and lock on to the wrong part of the subject.
David’s award-winning fly was just 2.4mm
in depth, and shooting at increments of
0.04mm required 61 images to make up
the final picture.
His apparatus may look slightly comical,
but watching David work his magic is
amazing. From the freezer he produces
a fly he caught earlier (see page 25 for
information about caring for your subjects).
After some early misadventures trapping
insects, David now uses a Pooter, a more
humane apparatus used by entomologists
and pest-removal experts that gently sucks
up the insects into a tube and holds them
against a soft filter until the inhalation is
reversed and the insects drop into a jar.
Once David has his subject, he carefully
places it inside one half of a ping-pong ball
that has been cut in two. This helps to diffuse
the two studio lights he uses to illuminate
the subject, and it reduces unwanted
highlights in the fly’s eyes or body. Attached
to a clamp is his Canon EOS 40D, fitted with
a 35mm f/2.8 bellows lens, with a special
microscope thread attached to the Canon
FL bellows. On the back of his camera he
has an FL-to-EF adapter, while on the front
he has another fitted to take the lens. With
the lights on and the ISO at 100, David
takes an exposure reading using AV mode.
With the mirror in lock-up position and
Enlarger lenses
Using a bellows unit like
David’s can give you a much
closer look at your subject than
using ordinary extension tubes,
and using an old enlarger lens
in reverse can give you even
greater magnification at an
inexpensive price. Enlarger
lenses were designed for
projecting magnified versions of
a negative onto paper. While in
the darkroom the back of the
enlarger lens would be closest to
your negative to project a larger
version of it onto your paper,
here you can turn it around so
that the back of the lens faces
your subject. In essence, you are
using the lens within its original
design conditions and exploiting
its low field curvature and high
resolution, thus making it idea for
David’s ‘super macro’ technique.
Lacewing made
from 41 separate
source images
Canon EOS 40D,
Nikon E Plan 4x/0.1
microscope objective
lens, 0.8sec, 0.015
increments, mag
7x, ISO 100
‘Maybe it’s my scientific
background that attracts me
to the apparatus required for
this super-macro work’
David’s camera
setup with his
home-made
increment chart
that shows depth
of field at each
aperture and
focal-length
combination
using a remote shutter, he fires a test shot at
1.3secs at f/4, which is the best aperture for
resolution, he says, with this lens.
Once set up, the photographic process is
simple. With the lights on, he takes the first
shot and then adjusts the focus backward
0.04mm. He takes his second shot, winds on
the focus another 0.04mm and keeps doing
this all the way across the subject until he
reaches the end. ‘I don’t focus visually,’ says
David. ‘Once I know the increments, I wind
the camera backwards on a micrometer
[a device used in mechanical trades for
precision measurement] and press the
remote shutter release at every increment.’
David sometimes uses an adapter ring to
reverse old enlarger lenses, which allows
for even greater magnification (see Enlarger
lenses, left). He also makes his own bespoke
adapters to attach lenses to his bellows.
To add an extra element to his images,
David has a collection of small coloured
background cards that can be lit separately
for special effects. While adding colour
and achieving a perfect exposure aren’t
problems for David, his biggest obstacle is
a lack of space between the lens and his
subject. When using his microscope lens, the
working distance from lens to subject can be
as little as 5mm, he says. ‘That’s when it gets
tricky, but it’s also when the fun starts. It’s
when you need to get creative.’ AP
26 www.amateurphotographer.co.uk I 17 April 2010 subscribe 0845 676 7778
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