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The
Collins English Dictionary defines ergonomics as "the study
of the relationship between workers and their environment"
and at first glance you would be right in wondering what on
earth that's got to do with underwater camera equipment.
Well,
taken through logical steps, it also means the relationship
between camera housing controls (the environment) and the
fingers which operate them (the workers).
Ergonomics
is not something which is discussed too much by underwater
photographers, but it is an invisible important factor in
the quality of results you produce (hence the dictionary definition
of workers and environment). Taking time to appreciate the
finer points of ergonomics will give you a fuller understanding
of the relationship between form and function and could save
you from buying a system which is not ergonomically ideal.
From
an underwater photographers point of view, ergonomics starts
with the hands and in particular where the main controls fall
in relation to your fingers when holding the camera in its
natural position. The most important is the shutter release
lever.
When
you pick up almost any land SLR camera, your left hand cups
the bottom of the camera, your left index finger and thumb
line up around the focus barrel of the lens ready to focus
the lens while your right hand holds the camera and leaves
your right index finger free to operate the shutter release
lever. It was not a mistake that, on manual wind-on cameras,
the wind-on lever was just behind the shutter release lever
where your thumb was ideally placed to operate it. That's
ergonomics.
The
next relationship is how you can control the camera without
having to move your hands away from the natural holding position
and without having to take your eye away from the viewfinder.
The two important controls are the focus and aperture, the
former of which is probably the most used. You should be able
to operate the focus control without having to reposition
your hand away from its natural position. Since you will need
to focus before nearly every shot, the position of the focus
control is crucial to the smooth working of the camera.
In
addition to the actual positioning of the focus control there
is also the function of the control which is important. With
most macro lenses, the barrel of the lens must be turned around
360ø to go from infinity to closest focus and, if the
internal gearing of the focus control is too small, you will
need to make several turns of the focus control knob to go
from infinity to minimum focus. Whilst this is not a major
problem, given a little extra time, it is possible to design
control gearing to emulate the focus barrel of the lens i.e.
a 360ø turn to go from infinity to minimum. This is
the best form of control and will definitely aid better focusing.
This action becomes less important when using wide-angle lenses
because the focus barrel of these lenses does not turn as
much as a macro lens.
The
aperture position is more important than the shutter speed
control in most cases as the latter tends to be pre-set, especially
when using electronic flash. The aperture is something you
usually want to adjust as the camera to subject distance varies
and you should be able to do this without having to take your
eye from the viewfinder and without having to move your finger
away from the shutter release lever.
Zoom
is another control on a reflex housing which should be able
to be controlled without taking your eye away from the viewfinder.
This control should be similar to the focus control i.e. geared
to emulate the lens movement and also be placed in such a
way as to be easy to operate.
Another
ergonomic design should be how the camera is mounted in the
housing. The correct position is so that you can change film
without having to remove the camera from its mounting and
most modern designs do achieve this.
It
is rarely possible to produce an ergonomic design if the housing
can accommodate more than one manufacturer's camera i.e. Nikon
and Canon. Whilst most manufacturers make similar-shaped cameras
(the Nikon F601 and F801 are virtually physically identical),
another manufacturer's camera design will almost certainly
be different and controls will have to be repositioned to
cater for the differences in design. This repositioning will
almost certainly affect the ergonomics detrimentally.
A
final consideration is the ergonomics of balance and buoyancy,
for a housing should ideally be neutral and easy to hold level
for long periods of time. It is surprising how even the slightest
imbalance can become an irritation during an extended dive
and a good design should avoid this.
So
there we have ergonomics - you often can't see it, but it
definitely makes the difference between an easy to use design
and one with irritating short comings. Next time you pick
up a land camera or an underwater housing, think ergonomics.
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