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| This is my Mockup #13 with the lens removed so you can see how the fingers of the right hand lie in the natural 'half closed-relaxed' position when holding the handle. The shape of the handle and the location of all the control modules were dictated by the functional anatomy of the hands and fingers. This mockup is very comfortable to hold and the controls are all placed where the fingers want to find them so they would be very easy to operate. |
I
propose a framework for describing, analysing and thinking
about camera ergonomics as follows:
There are four
Phases of camera use
1. Setup. At home, with the Instruction Manual to hand
and no time pressure, go through the Menus and make desired settings.
2. Prepare. This refers to the few minutes just prior to
a photo session when the camera must be configured for new subject matter. This
might be landscape, portraiture, sport/action, long night exposure and so
forth. Typically items requiring adjustment might include Main Capture Mode,
Focus Mode, Autofocus Mode, Drive Mode, Quality, Stabiliser and numerous
others.
3.
Capture. In this Phase
the user is making photos. Any adjustments must be made efficiently without
interrupting the capture flow.
There are three ways in which the user interacts with
the camera in Capture phase. These are
* Holding
Desirable characteristics
are:
That the shape of the
camera on the right side encourages the user to hold it using the ‘half closed,
relaxed’ natural hand position. When
thus held, the camera is firmly yet comfortably held without undue muscle
effort. Key user interface modules (UIMs, buttons, dials, levers,
switches) for controlling primary and
secondary exposure and focus parameters are exactly where the right index
finger and thumb want to find them without having to shift grip.
The shape of the left
side of the camera and lens and/or lens barrel encourage a natural posture of
the left hand and fingers without undue need for displacement at the
wrist. Key tasks such as zoom and manual
focus can be easily performed by feel while continuing to support the mass of
the lens. (See more on this in Part 5)
* Viewing
Desirable characteristics
are:
There is a clear,
accurate preview of the subject via an eye level viewfinder and monitor. The
same information is presented the same way in both for a seamless segue between
them. Key camera data can be clearly displayed or not as user selected. (See
more in Part 5)
* Operating
The two main
considerations when operating the camera are
* Tasks
Typically items requiring
adjustment in this Phase include primary and secondary exposure and focussing
parameters.
Desirable characteristics
are:
The
user can adjust primary and
secondary exposure and focussing parameters while looking continuously through
the viewfinder and without having to change grip with either hand.
Primary exposure
parameters are Aperture, Shutter Speed, Sensitivity (ISO).
Secondary exposure
parameters are Exposure Compensation, White Balance.
Primary focus parameters
are Initiate AF, Perform MF.
Secondary focus
parameters are Change position and size of AF area, Switch AF/MF.
That does not mean every
task on the list must be carried out for every exposure but the camera should
be designed and configured so the user can efficiently carry out the tasks
required for a particular exposure.
* Haptics
Desirable characteristics
are:
That all UIMs for Capture
Phase actions lie readily to hand when the camera is held comfortably in
landscape or portrait orientation. UIMs for Capture Phase are easy to locate,
distinguish from each other and operate
by feel.
UIMs should not be
located where they are prone to unintentional activation.
4.
Review. In this Phase
the user reviews photos already captured.
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| How not to do it. This is the original Sony A7 MILC. The upper yellow oval represents the index finger on the shutter button. The lower yellow oval is where the middle finger must be placed. the distance between them is about 50mm forcing an extreme displacement between the index and middle fingers. The persons responsible for this camera need to read my blog. The Mark 2 versions of the A7 have a projecting handle with the shutter button in the forward position. This is an improvement but still well short of ideal. |
Summary
Each Phase of use requires the user to carry out tasks.
Desirable characteristics for each task group can be
listed in the form of a specification.
Completion of each task requires actions.
The number and complexity
of actions can be observed and recorded. This is a type of motion study as pioneered
by Frank and Lillian Gilbreth.
I do not directly observe the time taken to complete
the various tasks. I take the view that economy of motion is the primary goal
and that a device which can be operated with a small number of simple actions will
be quicker to use than one which requires more and/or more complex actions.
The task specification and motion study information
can be used to develop an ergonomic score for that camera.
Holding, Viewing and Haptics can also be evaluated and
scored. I note that an individual user’s
assessment of a camera’s holding, viewing and haptics contains both objective (observation)
and subjective (experiential) elements.
Some people have difficulty with the idea that
subjective experiences might be evaluated and scored but in fact this can be a
valid and useful exercise if done with
appropriate guidelines.
The
essence of camera ergonomics
In one sentence, I propose that
Of
two cameras, the one which can be operated with the fewest, least complex
actions has the better ergonomics.
I also propose that ergonomics is not about:
* Individual likes and preferences. These are of course a valid part of the user
experience but are separate from and complementary to the ergonomic analysis.
The problem with likes and preferences is that they
are idiosyncratic (relevant to one individual only) transient (will change next week or month
in response to the person’s experience) and often poorly formulated (‘I
love/hate that camera but I can’t really say why’) .
Feedback from clinics, consumer surveys and focus
groups has the same problems. It may well be useful for marketing purposes but
does not helpfully inform the ergonomic design process.
An example: I have discovered that canting the handle
back ten degrees is a really good idea. But this would be most unlikely to
emerge from a focus group because people usually only talk about those things
which are already within their experience.
* Head logic. Ergonomics is about finger logic. This issue arises most often when considering
the merits of the ‘traditional’ control system versus the ‘modern’ system. The
traditional system with aperture ring, shutter speed dial and exposure
compensation dial is simple and logical.
One respondent to my posts said it is therefore “blindingly
obvious” that the traditional system is the best.
But operation of a camera with the traditional system
requires more actions most of them more complex than is required to operate a
camera using a well designed modern system.
It occurs to me that some people might wonder if voice control could provide a more efficient
way to operate a camera. I think this is highly unlikely. The problem is that
the intention to adjust something has to be sent to the part of the brain which
codes that idea into speech, then on to the part of the brain which transforms
speech codes into nerve impulses, then on to the voice musculature. It is much
faster to just do something like, say turn a dial to change the shutter speed. With practice muscle memory makes the process
automatic.
Imagine driving a motor vehicle by voice control.
….’Turn left now’…..oops……not that far….. crash…….sorry…………
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