During
the last year, I have been trying out a technique called zoom
blur and have had the chance to show a couple of the resulting
images at BSoUP meetings. Zoom blurring is achieved by zooming
a lens while the camera's shutter is open. This records an
abstract image with zoom lines radiating from the centre of
the photograph, produced as the zooming alters the size of
the subject in the frame. In this article I hope to pass on
some of my experiences with this technique.
An
acroporid coral and anthias in The Alternatives, Sinai, Egypt.
Nikon F100, 17-35 mm Nikkor (zoomed through full range), 50
CC Red filter (depth = 5.0 m). On f22, aperture priority -
exposure time approx. 1/2 to 1 sec. Kodak Ektachrome Extra
Colour 100.
I
would like to say that it was a result of inspired forethought
and detailed planning. But in truth, it was two events on
a BSoUP Red Sea trip, which were quite beyond my control,
that led me to try the technique of zoom blurring underwater.
The first was a lunchtime chat with Colin Doeg, the BSoUP
Chairman, who was offering the opinion that underwater photographers
could produce some really original images if they tried out
more of the photographic techniques used by land photographers.
At the time, I did not agree, arguing that because of the
technical difficulties of producing clear, sharp and colourful
images underwater, we cannot easily import techniques used
on land. The second event was far less pleasant! On my penultimate
night on board my flash guns packed up. And after an unproductive
session with a multimeter and the extensive use of expletives
of similar colour to the ocean, I made the executive decision
that my final day of shooting should be a "natural light"
day!
The
next morning I stuck a 50 CC red gel filter to the rear element
of my 17-35 mm zoom, detached my flashes and arms and set
off on a 4 m dive. At four metres a 50CC red filter will provide
approximate colour correction in blue water, so there was
no need to go deeper. Or shallower, a colour correction filter
must be the best way to keep an underwater photographer from
diving sawtooth profiles! The amount of colour correction
needed is estimated as 12 CC units of red filter per metre
of light path from the surface, to the subject and on to the
camera.
The
fastest film I had with me was 100 ASA, which even at 4 m
only gave me exposures of 1/60th at f2.8 through the filter.
So after a few shots fighting the lack of depth of field,
I decided to work with the lack of light and try some long
exposures, sticking my camera on aperture priority and stopping
down to f22. One of the advantages of using filters for long
exposures is that the colour spectrum of the image is consistent
and correct throughout the exposure. When we use flash in
long exposures (such as rear curtain) the flash light has
a different colour balance to the rest of the exposure, which
may or may not be pleasing.
At
f22 I got exposure times of between a half and one second.
Such long exposures gave me time to think, my thoughts returned
to Colin's comments from earlier in the week, in particular
the technique of zoom blur. So, in order to relieve my boredom
while the shutter was open, I decided to try zooming the lens.
I was operating on guess work, and I didn't really know what
sort of mess I was making on the film!
Fire
coral and anthias in The Alternatives, Sinai, Egypt. Nikon
F100, 17-35 mm Nikkor (zoomed through full range), 50 CC Red
filter (depth = 4.1 m). On f22, aperture priority - exposure
time approx. 1/4 to 1/2 sec. Kodak Elitechrome Extra Colour
100.
In
general, I got my best results by zooming from wide to short
focal lengths, and I prefer the images where I left the lens
at the wide end for a few moment before zooming, which produced
a well defined background onto which to overlay the zoom blur.
The characteristic trails produced by zooming are clearest
when dark and light subject matter are juxtaposed, such as
light corals and dark blue water. Large blocks of solid colour,
such as open water, do not produce trails but make an effective
background for trails or improve composition by providing
negative space within the image. I would recommend wide-angle
zooms for this technique underwater, and if possible a lens
with a constant aperture throughout the zoom range.
In
order to get accurate colours I "bracketed" the
correction by taking pictures at several depths within a metre
or so of 4 m. With the benefit of hindsight, I don't think
that this was necessary, because accurate colour correction
is not essential for such abstract images. It is also worth
noting that with an SLR you certainly cannot believe your
eyes when looking through a colour correction filter! At 4
m the filter worked well on the film, but in the water my
vision had adapted to the in situ colour spectrum and the
view through the camera looked far too red. The bottom line
with colour correction is to trust your depth gauge and not
your eyes.
One
consequence of long exposures is keeping the camera stationary
during exposures. A tripod is good solution although it is
not a typical accessory for underwater photography in the
Red Sea. Certain dive sites lend themselves to long exposures:
wrecks for example provide a number of places where we can
brace a camera. In the Red Sea, I produced acceptable results
by hand holding the camera.
After
my experience with zoom blur in last summer, I fully recommend
that it is always worth taking a break from the tried and
tested techniques that we have profited from in the past.
Also, I now agree with Colin that adapting a technique from
another branch of photography can produce original and unusual
images underwater! And next time I may even try out some of
these techniques when all my kit is fully functional.
An
additional thought!
But
before rushing out to give zoom blurring a try I feel I should
also let you know that this effect can easily be imitated
using the wonders of Photoshop! Zoom blur can be added to
any image by using the zoom function of radial blur (Filter:
Blur: Radial blur). It is worth noting that the computer has
several advantages over the camera as well as meaning you
don't have to get wet. First you can select any photograph,
including colourful flash lit images, from macro to fisheye.
Also the extent of zoom blur is precisely user defined, and
the origin of the blur can be set anywhere within the image.
When the technique is produced in camera the origin is always
in the centre of the image.
Coral
trout on reef, Sha'ab Abu Nuhas, Egypt. Nikonos V, 15 mm UW-Nikkor.
Sea and Sea YS120 flash gun. On f8 aperture priority (1/60th)
TTL. Zoom effect added in Photoshop to right hand image Filter:
Blur: Radial Blur.
This
image of similar subject matter to the in camera shots shows
the before and after effect of a single application of radial
zoom blur in Photoshop.
