Viewing Systems

CAMERA ERGONOMICS

Part 9  Viewing  Systems

Author  AndrewS 



Photo 1 Eye Level View Hold

When using a camera the operator needs to view two entirely different sets of information.   The first is  the subject, the other is a set of camera status indicators.  Each requires a different  cognitive engagement with the photographic process.  Viewing the subject means the operator looks throughthe camera at the subject.  Viewing status indicators means the operator has to look at  the camera itself.  A well designed camera will allow the user to integrate both cognitive processes in a seamless fashion.            How should this viewing take place ?

Photo 2 Monitor View Hold

Modern cameras are provided with either or both a monitorwhich is like a small computer monitor on the back of the camera and an eye level viewfinder  (ELV) which can be one of the several kinds of optical viewfinder  (OVF) or an electronic viewfinder (EVF).  Some cameras have a hybrid OVF/EVF.  Visual information can be found at either place and also on various levers, dials or display panels located on the camera body.

The term live view is often used in descriptions of various kinds of viewing system.  Early digital SLR's could display on their monitor a review of the last shot captured but not a preview of the scene being presented to the camera. All compact cameras and mirrorless Compact System Cameras do  display such a preview on their monitor. This is referred to as live view. Recent generations of DSLR's also enable live view on the monitor but only by raising the flipping mirror which disables the optical viewfinder.  Compact System Cameras with inbuilt EVF allow live view on both the monitor and EVF.  Optical viewfinders have always presented a "live view" to the user.



Photo 3 Set and See Dials

Some cameras locate both visible status of  and control of Shutter Speed, ISO, Exposure Compensation, Shooting Mode and Drive Mode to hard "set and see" dials usually on top of the camera body.  If carefully implemented this approach can be very efficient and can provide a good ergonomic experience for the practiced user. Snapshooters may not favour this type of layout as it tends to look a bit complex (although in use it may actually be quite simple) and it requires training and practice for effective use.   The big ergonomic advantage of this tactile/visual style of control layout is that the camera displays  essential  shooting information at a glance, all of which can be adjusted quickly and directly.  Some cameras hide this type of information in menus, resulting in a camera which is not well suited for use by either snapshooters or controllers.

Monitor view versus Eye Level view

With monitor view the camera is held away from the operator. This can be desirable when photographing people as the photographer can engage in conversation and eye contact with the subject(s).  The camera is less likely to be perceived as coming between the photographer and subject, literally and figuratively. In public places a  photographer may attract less attention using monitor view than eye level view. With monitor view it is easier to hold the camera high, low or off to one side, particularly if the monitor screen is articulated.

But there are several disadvantages to monitor view. In bright light and in particular direct sunlight the monitor is difficult or impossible to see. Even if the subject can be framed reasonably well, superimposed data will be unreadable.  Long lenses cannot be held steady. The user is always prone to being distracted by his or her surroundings.

 A well designed eye level viewfinder (ELV) is the solution to these problems.

The best ergonomic design provides for both monitor and inbuilt ELV. Optimally a sensor automatically activates the ELV  when required.

Some cameras provide for a clip on ELV. This option is much inferior to the built in viewfinder.   The clip on is likely to be on the camera when not required but in a camera bag or pocket somewhere when it is required.  It is prone to damage or loss.

Optical (OVF) versus electronic (EVF) viewfinder

The types have different characteristics which are of ergonomic significance.

There are two main types of OVF, SLR type and Rangefinder type. The rangefinder OVF provide a  direct and continuous view with no blackout during  or following image capture. However it is subject to parallax and other forms of framing inaccuracy, is unsuitable for closeup, zoom or telephoto lenses and is difficult to adapt for information overlays.  The SLR type OVF solves many of these problems but has it's own limitations. A  bright SLR OVF  has to be physically large with a substantial and complex optical arrangement.  It does not adapt  readily to information overlays.

The main problem for the OVF is that it has reached the end of it's evolutionary journey.

The EVF has many potential advantages some of which have yet to be fully realised in production versions.  These include 100% accurate field of view, constant brightness in bright or dim conditions, brightness varies to indicate the effect of  exposure compensation,  active AF area and size are clearly displayed, camera data can be displayed beneath and superimposed on the image and varied or switched off as required. Live histogram, electronic level and framing grid lines are easily displayed if required. Camera shake warning can be implemented.

Ideally the EVF should display the same information in the same layout as the monitor so the operator can shift attention seamlessly from one to the other.

A large, clear, bright, sharp EVF occupies less space than a high quality OVF allowing for a more compact camera package. I have discussed the optimum position for an EVF in Part 8 Locations.

The EVF has disadvantages too. It requires power which in turn requires more battery capacity. It only operates with the camera switched on. In the first quarter of 2012, most current EVF's have a refresh rate which is not fast enough for image preview with  rapid tracking of action at high frame rates.  Most also lack the dynamic range of an OVF leading to blocked up shadows and/or  blown out highlights in the image preview and review.

These issues are amenable to technological solutions which I expect will see the OVF replaced by the EVF in due course. Already it appears several major manufacturers have stopped making OVF's.

Data Displays 

Photo 4 Superimposed Data

Monitors and viewfinders have to allow the user to frame and compose the subject and also display many indicators of camera status.

My experience with many cameras leads me to the view that the best place for primary capture data is on a panel below the image preview/review and visible in both the monitor and eye level viewfinder, in exactly the same format and layout for seamless transfer from one view to the other.

Photo 5 Data on Sub Panel

This data includes Shooting Mode, ISO, Shutter Speed, Aperture, Analogue Exposure Compensation scale, Indication of Flash Exposure Compensation, Memory Card Remaining Capacity and Battery Status.  Many cameras superimpose this information on the image preview where it is much more difficult to see and interferes with image composition.

Monitors and  EVF's can superimpose on the image preview a great deal of additional information. This includes status indicator icons for just about anything including camera shake warning, plus electronic level, composition gridlines, live histogram and size/position of active AF/MF area.

The best ergonomic result is achieved when all of these options are user selectable, one by one or in groups.

Some cameras let you have, for instance, gridlines, or live histogram or electronic level but not any two or all three at once. This is particularly frustrating as the issue is probably software (firmware) related and therefore easily correctable.

Implementation

The precise manner in which data display is implemented makes a big difference to the user experience.   For instance I have two cameras which provide a camera shake warning. On one the warning icon is small, mid grey and still. I hardly ever notice it. On the other the warning icon is large, red and dances about on the screen. I always notice this one.

The precise implementation of the  live view histogram greatly affects it's usefulness. It's main value is  seeing at a glance if highlight clipping will occur. Therefore the histogram has to accurately reflect the effect of current exposure settings including exposure compensation.  The precise relationship between highlight tones and the extreme right limit of the scale has to be easily seen. If the histogram is any colour and it has a  bounding box of the same colour you will never be able to tell if highlight tones are clipped or not. The bounding box, if any, needs to be a very different tone or colour from the histogram data display.

Locations

CAMERA  ERGONOMICS

Part 8,  Locations

Author  AndrewS 



Photo 1 Holding the Mockup

Form and function       A modern electronic camera can have any shape and configuration at all.  It would be relatively easy for manufacturers to produce cameras shaped like a spheroid, a prism, cylinder or any other simple or complex shape.

Whatever it's shape a hand held camera will always be used by someone's ...... yes, you guessed it.........hands    and those hands do not change their size, shape or function  to conform to changes in camera design.   The design has to accommodate the hands, eyes and brains of it's users.

For the purposes of this discussion I will use a mockup with a fairly conventional layout. It has an efficient general configuration. The position and relationships between camera body, monitor, EFV, handle and most controls would all be immediately recognised by most people as a camera.

Camera real estate    Ask any real estate  agent the three most importand determinants of the value of a house.  The answer will be "position, position, position".  Camera real estate is just like that.  The user interface modules by which a camera is controlled have to be disposed around the camera body in some arrangement.

Some locations have a  high value because they are most easily reached by the right thumb and index fingers. To these locations we should allocate tasks of the highest priority in the Capture Phase of camera use.    Locations which are more difficult to reach can be assigned tasks for the Setup Phase of camera use. Please refer to Parts 9 and 10 for detailed discussion about the phases of camera operation.

I have identified four levels of  location value, High, Hi Medium, Lo Medium and Low.

The Mockup  Please refer to Part 13 for detailed discussion of the mockup used.

Assumptions  This discourse assumes we are dealing with a hand held camera suitable for use by a person who likes to take control of the photographic process.  In other words an expert, aspirational snapshooter or professional user.  The mockup has been designed and built by the author to represent the best size and configuration for a compact (mirrorless) interchangeable lens camera. It is optimised for an adult with average sized and shaped hands but the design allows easy use by people with larger or smaller hands.

This camera could also be quite suitable for a snapshooter when set to fully automatic mode. In this case most of the external controls would be rendered inoperative. Should the snapshooter desire to upgrade his or her photographic skills (s)he can do so using the same camera.

Photo 1, Holding    This photo shows the author's right hand holding the mockup camera. This is the starting position with the thumb sitting comfortably in it's indented space and the index finger resting on the shutter button. The other fingers are gripping the handle.

Notice the position and  orientation of the interface modules. The mockup might look a bit rough but the precise location of the control modules has been developed through many trials for optimum efficiency. The exact distances in millimeters between the modules and their exact layout is the result of many trial mockups.  This iteration represents a high level of synchrony between the functional anatomy of the hand and the detailed design of the device.

Locations Mockup Top

Photo 2,  Locations Mockup Top       Here is a closer view of the top of the camera. I have identified a group of four control modules as having "High" location value.  With reference to Sections 4 and 6, I have shown that the right index finger can easily and quickly operate four modules in this location, by feel, without having to look at the camera, while continuously looking through the viewfinder and without moving a muscle of any body part except the index finger.  This is an ideal location for tasks of the Capture Phase of operation. It is particularly well suited to primary and secondary exposure control tasks.  On this mockup the modules are Shutter Button (user assignable function), Main Control Dial (function depends on operating and/or shooting mode),  Button 1 (user assignable function), Button 2 (user assignable function).

Next comes the group of modules identified as having "Hi Medium" location value. Modules in this area can only be reached by releasing the right hand's grip on the handle and supporting the weight of the camera and lens with the left hand. On the mockup I have used this location for a Main Shooting Mode Dial and a subdial Drive Mode lever. These two modules are used for tasks in the Prepare Phase of camera use.

On the right side at the top are two modules, buttons, in this case, labelled "Lo Medium" value.  Of the four buttons in a row, the front two are easily reached by the index finger without changing grip.  However  a substantial shift in grip is required to get the tip of the index finger onto the third button even though it's center is only 12 mm behind the second button.  These modules are suitable for tasks of the Setup and Prepare Phases of operation. The tasking of modules in this location should be user assignable.

Photo 3 Locations Mockup Rear

Photo 3, Locations Mockup Rear     The rear of a modern electronic camera is a busy place so everything has to be positioned very carefully, so the user can operate the device efficiently while holding it.

Let us start with the locations I  have designated "No Controls".  I once had a camera with buttons along the bottom, beneath the monitor. Bad idea. When I did want to reach one of those buttons it was awkward. I had to lower the camera and  release the left hand from the lens to get a finger on a button. But if I left the camera switched on while carrying it on a neck strap, those buttons got pressed accidentally all the time.

The second location which must be free from control modules is shown on the right side. Most of this is left clear so the thumb can find a secure rest place without forever bumping into a control module.  I once had a camera with a main control dial located where I have indicated "Not Here !!!" in Photo 3. Trying to use this camera was  one of those "I can't believe they did that"  experiences. Whenever I tried to hold the camera securely my thumb impinged on the control dial, causing unwanted alteration to a camera status parameter.

Another  place where control modules should not be located is on the thumb rest. Buttons in this location are often pressed accidentally when the user is picking up or carrying the camera.  There are many complaints about this on user forums. I have a DSLR with two recessed buttons at the upper end of the thumb rest.  The recess usually prevents them from being actuated inadvertently. However it is easy enough to find better ways of implementing the functions which they serve.

I have designated two very specific locations as having "High" value. Please refer briefly back to Photo 1 for the position of the thumb in the basic rest hold.  Without significantly disrupting either thumb opposition or the purchase of the right hand on the camera, the right thumb can move a short distance to the left or right side, and can be pressed forwards, into the body of the camera, without flexing.

The module to the left side of the thumb is a JOG type lever which can be pressed in and/or moved laterally in any direction . To the right side is a button sitting against the side of the thumb rest. This is easily activated by moving or rolling the thumb slightly to the left. The function of this button is Mode dependent and user assignable to some extent. These two modules are well located to provide primary and secondary focussing controls in the Capture Phase of operation.

Next we have a group of interface modules to which I have designated "Hi Medium" location value. To activate these modules the right hand must be disengaged from it's basic grip, and camera support duty taken by the left hand.  However the right hand does not have to move very far so modules in this area can be operated quickly. Prepare and Review Phase tasks do well here.

There are two zones labelled "Lo Medium". Those in the lower part of and the yellow buttons below the four way controller are very suitable for Review Phase tasks.

Several cameras locate buttons on the left side of the monitor. This is a suitable place for Setup  and Prepare Phase tasks.  It is a very bad place for Capture Phase tasks. Some camera makers do not understand this and routinely locate controls for ISO and AF Zone movement on the left side of the monitor. For further discussion about this  please refer to the photos with Part 2 of this series.

Cameras with swing out monitors cannot have buttons on the left side of or below the monitor.

Last we have the green buttons which I have labelled "Low" value. These can be accessed with either the right or left thumb but not while the camera is in the process of  making photos. They are best suited to Setup Phase tasks.

All the control modules on the camera rear should be amenable to user configuration with an extensive list of options for each module.

Viewfinder location  On the mockup in the photos you can see I have placed the viewfinder (VF) close to the top left corner of the camera back. I did a lot of experiments with VF locations on different mockups and selected this as the optimum location when the camera is held in landscape (horizontal) orientation. In portrait (vertical) orientation an EVF in either SLR style location (top center) or rangefinder location (top left) will work equally well. As most still photos and almost all video capture use landscape format this means locating the EVF top left gives the best ergonomic result.         The benefits of this location are

* It allows the user to look straight ahead while viewing through the VF and if desired keep the left eye open to scan a broader view of the scene.

* It allows the top left corner of the camera to be pressed into the nasal and orbital bones of the skull for maximum stability.

* For right eye use it keeps nose grease off the monitor.

* It is no worse and maybe better  for left eye use than a VF located in standard SLR position.

For optimum effectiveness there are some specific ergonomic design requirements. The optical centre of the viewfinder is best located approximately 20-25 mm in from the left side down from the top plate of the camera body. The eyepoint needs to be set so the cornea of the eye is located the correct distance from the VF eyepiece when the camera is held in viewing position. There needs to be a soft rubber or similar guard around the VF eyepiece to block out stray light and center the eye on the optical axis of the VF.

Handles and Holding

CAMERA ERGONOMICS

Part 7   Handles and holding

Author  AndrewS



Photo 1 Five Handle Mockups

Early days    In the early part of the twentieth century, press photographers used large format Speed Graphic and similar cameras. By modern hand held camera standards, these things were huge, requiring one or more large sturdy handles so the user could support and operate the machine at the same time.   When medium format users took their equipment out of the studio and off  the tripod, they too, soon realised the benefit of a sturdy handle.

35mm    Rangefinder and SLR cameras for 35 mm film managed well enough without handles for many years. But camera bodies grew in size and weight with autofocus, motor drive, batteries and electronics. Heavy telephoto lenses became readily available.

The Canon T90 of 1986, known by users as "the tank"  was one of the first SLR's with a built in handle. This camera was very influential in setting the shape and style of most SLR and DSLR cameras right up to the present time. So great has this influence been that I think it is fair to say the T90 set the shape regarded by many people as that of a "proper camera". As a result, many cameras which are not SLR's or DSLR's and are not "tanks" but are in fact quite compact, have been graced by their designers with a handle similar to that on a big DSLR.  The ergonomic consequence of this has been unfortunate, as detailed below.

Types of handle     My research has concentrated on cameras for the mass market.  This includes DSLR's with sensors up to 24 x 36 mm, Compact System Cameras and Advanced Compacts with fixed lenses.  Some medium format DSLR's have large, elaborate handles which I have not studied.

I have identified four  basic camera handle types. These are No Handle, Mini Handle, Projecting Handle and Parallel Handle. Intermediate varieties are not uncommon.

The sucess or otherwise of any  handle is strongly influenced by several factors. These include handle width, height and shape. The exact location of the shutter button is of crucial importance.  A handle without a good thumbrest makes for a completely unbalanced grip so the position, size and shape of the thumbrest is of great importance. 

No Handle   A lightweight camera not expected to mount telephoto lenses, covered in non slip material and with sufficient space on the right side of the lens and monitor screen, can function reasonably well with no handle.  Some cameras feature a small bump or raised section on the front of the right side of the camera body. I regard these as a variant of the no handle type.

Mini Handle  As I write this in February 2012, there is a contest between manufacturers to produce ever smaller camera bodies. Many of these have insufficient space on the right side of the monitor for a comfortable thumb rest and insufficient width for a decent sized handle. So they get a mini handle, perched close to the right side of the body. The shutter button is often on the top plate of the camera, also located close to the right side. The result is a camera which does not provide secure purchase to the fingers of the right hand, which must be cocked back away from the right side of the camera body, leaving a space between the camera body and the palm of the hand. This gives an insecure grip requiring the left hand to provide almost all the support function for both camera and lens.

Projecting Handle   This is the type to be found on most DSLR's.  It  requires the hand to adopt an "opened" grip.  It works well on medium and large camera bodies which have a large enough handle to allow the hand and fingers to spread out to a comfortable position. The precise location of the shutter button and the exact sculpted form of the grip are of critical importance.

On small cameras the projecting handle is unsatisfactory for the simple reason that the hands which use the camera do not shrink to fit. Small DSLR's styled to look the same as medium and large ones do not have enough space on the right side of the lens for a comfortably contoured projecting handle. Compact System Cameras and superzooms are even smaller resulting in a complete mismatch between the handle shape, shutter button position, hands and fingers. These cameras require a different type of handle design.

Parallel Handle  My work with mockups and actual cameras leads me to the view that the parallel handle type is the best solution for all camera sizes. Basically the parallel handle is a projecting handle rotated 90 degrees anticlockwise (as viewed from above) so it lays along the front of the right side of the camera. Once again it is imperative that the shutter button be  located in exactly the right spot and the handle itself be carefully sculpted so the fingers fit comfortably. When the fingers gripping a parallel handle are flexed the compression force is directed  into the palm of the hand, making for a stable, secure hold on the camera.

The only issue about the parallel handle with which some may find fault  is that it requires slightly more camera width on the right side than the projecting or mini handle types.  However the  potential benefits are great.   In many cases increasing the width of a narrow camera by as little as 15 mm would allow a dramatic improvement in handle design and operating characteristics.    It would also allow the fitment of a larger battery, something many modern cameras desperately need.

Photographs

Photo 1, Five Handle Mockups  These are some of the  mockups I have made in the course of studying handle design. At the back are the Large Projecting and  Large Parallel types. These are DSLR size with a shutter button height of 83 mm. In the middle are the Small Projecting and Small Parallel types. These are Compact System Camera size with a shutter button height of 64 mm. At the front is a No Handle type.

On the large cameras the parallel handle is only 3 mm wider than the projecting type but provides a more closed and secure grip. On the small cameras the parallel handle is 12 mm wider than the projecting version and provides a dramatic improvement in grip.




Photo 2 Projecting Handle Large

Photo 2, Projecting Handle Large  This is a popular handle type which works reasonably well on medium to large cameras. However the open grip hand position is not quite as relaxed or secure as the half closed grip seen in Photo 3.




Photo 3 Parallel Handle Large

Photo 3, Parallel Handle Large   The camera body is the same depth but this type of handle allows the more comfortable half closed hand posture. Finger flexion force is directed into the palm of the hand. This means that when gripped tightly with the fingers the camera becomes more stable with no tendency to twist out of one's hand.

All this is a bit difficult to demonstrate in words and photographs, but is immediately apparent with the mockups in hand.




Photo 4 Projecting Handle Small Natural

Photo 4, Projecting Handle Small Natural   Here is a projecting handle on a small camera. Unlike the mockup in Photo 2, there is no natural way to hold a small camera with this type of handle. For this photograph, I held the mockup with the nearest approximation to a natural grip that I could manage.   You can easily see that my index finger is nowhere near the shutter button. It wants to find a shutter button at  a different location.




Photo 5 Parallel Handle Small Natural

Photo 5, Parallel Handle Small Natural  This mockup camera is the same size as that in Photo 4 but now it has a parallel handle. The ergonomic difference is like night and day. Now the right hand holds the camera comfortably with a natural half closed grip. The index finger falls exactly on the shutter button because I got my fingers comfortably positioned before selecting the optimum position for the shutter button.     The conceptual basis of this design was "Form follows fingers".




Photo 6 Projecting Handle Small Forced

Photo 6, Projecting Handle Small Forced   Many small cameras have a projecting handle, forcing the user to hold them as shown here. To get the index finger onto the shutter the whole hand has to be cocked back at the wrist, an unnatural posture. The palm of the right hand has to pull away from the right side of the camera body, destabilising the user's hold on the camera. It is not possible to firmly grip and to operate this camera at the same time. The left hand has to be placed on constant camera support duty. But the left hand also has to work the zoom collar and at times the  manual focus ring, if available.




Photo 7 No Handle

Photo 7, No Handle  For many years the right side of most cameras using 35 mm film was like this. If there is enough width for the fingers and thumb to find decent purchase on the front and back of the body and the shutter button is inset far enough (on this mockup it is 30 mm which is sufficient) and the surface of the body has a grippy texture and nobody is planning to mount a big heavy telephoto zoom anytime soon, then this design can be fairly satisfactory.




Photo 8 Mini Handle

Photo 8,  Mini Handle   This camera's body width to the right of the lens is insufficient to accommodate a full handle so it got a mini handle. The centre of the shutter button is inset only 20 mm  and there is no thumb rest as the place for a thumb rest is occupied by a control dial. 




Photo 9 Mini Handle No thumbrest

Photo 9,  Mini Handle No Thumbrest  This is the position into which the user's right hand is forced in order to operate the camera in Photo 8.  The palm of the right hand is thrust away from the camera. The wrist is cocked back to an unnatural position.  The lower right rear corner of the body is perched on the centre of the palm. The only body part actually gripping this camera is the middle finger of the right hand.  To add injury to insult, there is on this particular camera a misalignment of exterior body plates at the lower right corner causing a sharp edge which digs into the user's palm.




Photo 10 Getting it Right Mockup

Photo 10, Getting it Right Mockup   This mockup is 7 mm wider and 7 mm lower than the camera in Photo 8, making the two almost exactly the same size. Yet the mockup in Photo 10 provides a dramatically  improved human machine interface (HMI)  It  is a pleasure  to hold. It has an anatomically sculpted parallel handle, the shutter button is optimally placed exactly where the index finger wants to find it and there is a large, secure thumb rest. The right hand and all except the index finger paticipate in gripping the camera which can be operated with the hand and fingers exactly as shown in Photo 10.




Photo 11 Handle Dimensions

Photo 11, Handle dimensions  This is the same mockup shown in Photo 10. The body of the parallel handle is 37 mm wide. The centre of the shutter button is vertically above the left (as viewed by the user) edge of the main part of the handle and sits on the handle not back on the camera body.  These dimensions work well for a variety of hand sizes and shapes. Small hands move up the handle, large hands move down the handle. Both can achieve a good grip.

Hands and Fingers

CAMERA ERGONOMICS

Part 6,  Hands and Fingers

Author AndrewS 

Introduction   In Part 4 of this series I explored the functional anatomy of the hand. The vast majority of cameras are hand held devices.  Clearly therefore, the manner in which the hands and fingers interact with the camera is of critical ergonomic importance especially in the Capture Phase.

Left Hand          On cameras with interchangeable lenses and most super zoom types, the left hand has two main duties. It must support the weight of the lens and sometimes, when the right hand is busy adjusting things,  most of the weight of the camera body as well. Part of this supportive role is to hold the camera/lens unit steady to prevent blurred photos.

The second main duty is to operate controls, while maintaining the support role.  From the days of all manual, film based photography, traditional controls allocated to the left hand were manual focus and aperture setting. With the advent of zoom lenses, operating the zoom action was added.  In the electronic era, controlling lens aperture is usually carried out by the right hand.   Indeed, there is no technical reason why the left hand needs to control any function of an electronic camera or lens, given the availability of power zoom and powered manual focus.

However in the interests of dividing labour between the hands it can be desirable to allocate some controls to the left hand. Let us consider what kinds of actions the left hand can perform.

In the Prepare Phaseof camera operation the left hand does not have to support the lens/camera unit, except in a very general fashion so as to prevent it falling on the ground. In this phase the left hand can reach and operate a variety of interface module types. These include

* On the lens or the left side of the camera body: Switches, dials, buttons and levers.

These can be used to make settings in the several minutes prior to capture, at a time when the operator is not looking through the viewfinder and can therefore look directly at each control module.

In the Capture Phaseof operation a very different set of ergonomic imperatives prevails. Now the operator is looking at the subject through the viewfinder and must carry out all control operations by feel.  In this situation the principal type of  interface module which can be reliably operated by the left hand is

* Rings/collars around the lens barrel.

If these are positioned, sized and shaped properly, they are easy to locate and operate by feel with the camera in landscape or portrait orientation. They need to be positioned so the left hand can continue it's support role while working the rings.

Left hand capture phase controls, including primary and secondary exposure and focussing controls should never be allocated to the kinds of interface modules (buttons, dials, levers, switches) suitable for Prepare Phase tasks.

Why?  Because the left hand cannot be in two places at the same time. Either it is holding and supporting the lens barrel or it is pressing a button on the left side of the camera or somewhere on the lens.

Some camera makers locate buttons for ISO and/or AF (the button which allows active AF position to be moved) on the left side of the camera body. ISO is a primary exposure variable. AF position is a secondary focussing variable. Both belong in the Capture Phase of camera operation. With such a camera, if you want to change ISO or shift AF position, you must stop the capture process, drop the camera down from the eye, remove the left hand from the lens, press a button, return the left hand to the lens, then make the adjustment with the right hand. During this tedious process, any mobile subject will have left the field of view. Forget about capturing critical moments.

Note that levers or buttons on the lens barrel may seem easy enough to find with the camera in landscape orientation, but will be unreachable when the camera is flipped over to portrait orientation.

In an electronic camera just about any function could be allocated to lens rings.  Newcomers to photography might not have any preconceived expectations about this but old timers will be looking to find controls for manual focus and zoom located on the lens barrel.

Example: Lens barrel interface module location and type

Photo 1

Photo 1, Lens Barrel Good Design.  The maker of this lens appears to have a good understanding of the distinction between Pepare and Capture Phases of operation, leading to an ergonomically appropriate choice of correctly located interface module types.  Thus we see large, ribbed, rubberised rings for Zoom and Manual Focus, both required in Capture Phase. These modules are easy to find and operate by feel, using landscape or portrait camera orientation. You can also see the  Set and See sliders for Focus Range, AF/MF, Stabiliser On/Off, Stabiliser Mode 1/2. These four parameters require adjustment in the Prepare Phase when it is quite appropriate to drop the camera down from the eye to look at the sliders and adjust them.

Photo 3 Find and press the iFn button




Photo 2 Basic hold

Photo 4 Find and rotate the focus ring

Photos 2, 3, 4, 5   Lens barrel iFunction. The maker of this lens encourages users to adjust Aperture, Shutter Speed, Program Shift, Exposure Compensation, White Balance, ISO and other parameters by pressing a button labelled iFn on the lens barrel to activate the feature then rotating the focus ring to make the adjustment. Most of these parameters require adjustment in the Capture Phase of operation. This camera provides ergonomically simple and direct means of adjusting each of these parameters on the camera body so the reasoning behind the iFn concept is a mystery to me. Perhaps the marketing department wanted a unique selling proposition, I don't know.

Photo 2 shows the basic camera/ lens hold position. To adjust any parameter you must first find the iFn button on the side of the lens  (Photo 3)  which is not easy as it is not prominent and not located near a finger with normal hold in use. Then you must press the iFn button repeatedly until the required parameter is displayed in the viewfinder, at which point the cognate parameters normally displayed in the EVF  such as shutter speed, ISO etc are overlaid by the iFn graphics and therefore invisible. So if you adjust Aperture, the effect of doing so on the Shutter Speed is not seen. Then the fingers of your left hand have to shuffle towards the front of the lens searching for the focus ring. (Photo 4)  This is then rotated to change the selected parameter and the change confirmed with a half press of the shutter button.  

Photo 5 Portrait hold,  iFn button inaccessible

When you turn the camera 90 degrees for portrait framing (Photo 5) the iFn button disappears beneath the left hand and is virtually inaccessible.

A straightforward  time and motion study shows that the process of making any adjustment via the iFn button is much slower, requires more module activations and requires more finger stretches than the same adjustment on the camera body.  It's a kludge, but some users report that they "like" it.

It appears the maker and some users of this equipment have yet to reach a clear understanding about  what types of interface module work best in the different Phases of camera operation.

Right Hand      Like the left hand, the right hand has two main duties, holding/supporting the camera and operating the controls.  Each finger of the right hand has a specific functional capability which defines it's optimum role.

The index fingerof the right hand is uniquely qualified for some of the most critical tasks in the  capture phase of operation. It is for most people on the dominant side, it has excellent touch and position sense and it does not have to grip the camera. For these reasons it is almost universally tasked with pressing the standard two stage shutter button.  In addition  it can efficiently control primary and secondary exposure and focussing variables.      Referring back to  Part 4, the index finger can, by touch, without having to look at the finger,  efficiently control four user interface modules, provided they are correctly located.

Consider the outcome of allocating the following items to these four modules:

1. Shutter button (on half press, activates auto focus and  auto exposure metering, on full press makes exposure) 

2. Top front main control dial (function depends on Shooting Mode)

3. ISO button  (press to activate, change with control dial, confirm with half shutter press)

4. Exposure Compensation button (press to activate, change with control dial, confirm with half shutter press)

Let us give this camera a rapid means of switching exposure modes, for instance a Set and See  shooting mode dial sited on top of the camera where it can be seen at a glance.

Now the user can quickly, by feel, without looking at any of the physical controls, without shifting grip with the right or left hand  and while viewing the subject continuously through the viewfinder,  carry out the following tasks:

* Adjust shutter speed, aperture or program shift (depending on which shooting mode is set).

* Adjust ISO.

*  Set exposure compensation

 * Start/Lock autoexposure

* Start/Lock autofocus

* Make the exposure

The thumb of the right hand has two tasks, gripping the camera and operating controls. It has to do both these tasks simultaneously making for a conceptually difficult design brief.

Let us examine gripping first.   everal design features must be in place for the thumb to be able to grip the camera in a relaxed but secure fashion. This will be possible when the right hand in basic camera hold position is able to adopt the "half closed relaxed" posture described in Part 4.  This requires:

* Enough width between the right side (as viewed by the user) of the monitor screen and the right edge of the camera body. There is no magic number but 50-55 mm combined with good contour design is about right. Some cameras manage decently well with only 40 mm.

* A carefully shaped, sized and angled thumb rest on the right upper part of the camera back. This must be contoured anatomically so the camera fits the user, not the other way around.

* An indented area clear of any control modules or intrusions on which the ball of the right thumb can comfortably rest in the basic grip position. This is located immediately to the left of the thumb rest and needs to be of sufficient size to accommodate even large thumbs without inadvertently activating a control module.

Now let us turn to operating.

Referring back to Part 4, there are, in the functional sense,  basically two actions which the thumb can carry out.

First are actions which maintain opposition of the thumb metacarpal and therefore grip.  A small amount of side to side movement at the carpometacarpal joint will not unduly interfere with opposition. It is also possible for the thumb to make limited flexion movement at the interphalangeal and carpometacarpal joints without unduly disrupting opposition.

Putting these two actions together in the Capture Phase of operation,  it becomes reasonable to ask the thumb to operate one user interface module immediately to the right of the rest position and one immediately to the left.

These modules could be assigned any of the tasks  required in the Capture Phase of operation,  but I propose an ergonomically consistent approach.  The logic of this is similar to the way motor car controls are laid out. It would be perfectly possible for a motor car to be steered with the feet, which would shift power control and braking to the hands. But such a car would cause instant carnage on and anywhere near the roads because people would not be familiar with it's ergonomics.  I presume nobody will die as a result of confusing camera design but inconsistent control layout between one camera and the next makes the process of taking photos less enjoyable and results in missed moments.

So the approach which I propose is to allocate exposure tasks to the index finger and focussing tasks to the thumb.

In this allocation of tasks the index finger would function as described above.

The thumb would have two duties to perform in the Capture Phase of operation. These are

* Start/lock autofocus (a primary focussing control) [or video in Movie Mode] with a button immediately to the right of the thumb at rest position and activated by moving or rolling the thumb about 5 mm to the right.  Allocation of start/lock AF to half press shutter button would be possible for users who prefer to operate that way.

* Move position of active AF area (a secondary focussing control) with a JOG type module immediately to the left of the thumb at rest position. This can be pressed in and also moved in any direction up, down left or right.

Note that in modes of camera operation other than still capture (Menu scrolling, Movie, Image review) the JOG module would perform different tasks.

Next we come to actions of the thumb which require undoing opposition of the metacarpal and therefore releasing secure grip on the camera with the right hand. This in turn means that while these actions are being carried out the left hand has to support the camera.

Consider the layout of a camera. On the right side there is an area bounded by the monitor, top,  bottom and right side of the camera body. I call this the "control panel".  We have thus far been considering actions occurring at the top of the control panel. Now we consider actions requiring the thumb to move down to the middle and lower parts of the control panel. This movement of the thumb forces the metacarpal and in some cases the whole palm of the hand away from the camera.

In consequence, Capture Phase actions should not be allocated to the middle and lower zones of the control panel. This is the place for Prepare and Review Phase actions.

Photo 6 DSLR Basic Hold

This is illustrated in Photos 6, 7 and 8.  Photo 6 shows a DSLR in basic right hand hold. This camera has a well designed handle and thumbrest for a comfortable and secure basic hold. However shifting AF area position is allocated to the 4 way controller low down on the control panel. Photo 7  shows that to change AF area position (a Capture Phase task) the right hand has to be completely removed from it's secure grip, requiring the left hand to take on all camera support duty.

Photo 7 Shift Active AF Area

There is a much better way.  Photo 7 also shows a white X in a white rectangle just above the Menu button.  If a JOG lever were to be placed at the white X, it could be tasked to directly shift AF area position. Photo 8shows the right hand position with the thumb directly over the white X.  The JOG lever needs to be precisely located in three dimensions so the thumb can operate it without flexing at the interphalangeal or metacarpophalangeal joints, either of which would disrupt grip integrity. Please refer to Part 4 for more discussion about this.   

Photo 8 Shift AF Area with JOG Lever

You can immediately see that shifting AF position this way would be much faster and smoother than the method actually provided by the manufacturer. The Movie and Menu buttons can be shifted to accommodate the new JOG lever. The Menu button is inappropriately placed in a high real estate value location anyway. It is used for Setup Phase tasks, so it can be placed  in a low value real estate location, such as the left side of the viewfinder.

Last but by no means least, we come to the middle, ring and little fingers. These generally operate together as grippers.  An anatomically shaped and positioned handle on the front of the camera is essential for proper grip. This is such an important topic I have given it the whole of Section 7.

These middle and ring fingers can also have a limited role as controllers. It may be possible with some camera layouts to  locate a button near the right (as viewed by the user) lower quadrant of the lens mount on the front of the camera. This could be easily accessed by either the middle or ring finger and used for a Prepare Phase action.

Basic Concepts of Camera Ergonomics

CAMERA ERGONOMICS

Part 5  Introduction to some basic concepts

Author  AndrewS

Introduction    Modern cameras have a vast array of features, functions, modes, options and controls.   Mirrorless interchangeable lens technology has given birth to a plethora of cameras with different shapes, styles, formats, capabilities and sizes, the like of which has not been seen before in the history of photography. Designers of these electronic marvels want  to produce brilliant products, each with a unique selling point,  which will convince prospective buyers to say "Here is my money, I will buy it".

But there are three elephants in the room with those designers.  Yes, they need a really big room !!

The first is that the native capabilities of  the people who use these cameras have not changed much in the last 50,000 years or so.  Sure, users can learn new skills, but they cannot change the size or functional anatomy of their hands.

The second is that beneath the fancy electronic bells and whistles, the great majority of modern cameras work just the same way as cameras did 100 years ago.  Exposure is controlled by alterations to the Time Value (Shutter Speed), Aperture Value (Fstop) and Speed Value (ISO Setting). The lens must be focussed, unless one is using a Lytro Light Field camera, but that is a story yet to be told.  All this must happen in good time, lest one's subject wander off  before the camera work is done.

The third is that despite some very clever technology, fully automated exposure and focus does not always deliver the required outcome. In consequence the world still needs cameras which can be directly controlled by the user.  These cameras have a complex human machine interface (HMI) and are difficult  to design well. I know this last statement must be true because I  have, in the last few years,  encountered so many cameras with a clumsy HMI.

Conceptual complexity    I want to highlight two fundamentally different types of problem, both of which challenge camera designers and engineers.

The first type of problem is conceptually easy buttechnically difficult to solve. The design of a camera sensor is like this. The concept is straightforward enough. Sensors need better resolution, lower noise, better color reproduction,  higher dynamic range and faster refresh rates.  In other words, the questions which need to be answered are reasonably easy to articulate. Of course, the technological challenges are great.

The second type of problem is conceptually difficult but technologicallystraightforward. Achieving good camera ergonomics is like this. There is currently a deficit of language and classification by which to articulate the questions which need to be answered in order to achieve good ergonomics. There is an old saying........"If you don't ask the right question you cannot get the right answer". This is a key issue for ergonomics.

The technological challenges are not great. They involve such things as camera size,  handle shape, type and location of controls, all things which have to be decided  with any camera.

My experience with many cameras over a 50 year time span is that camera makers are much better at dealing with technological challenges than conceptual issues in the realm of ergonomics.

Camera users   In the operational sense, there are really only two types of camera user.  The first and by far the most numerous is the snapshooter. The snapshooter is too busy enjoying life to be bothered with changing lenses or wondering what an f stop might be. In the second, smaller but more demanding group we find the  controllers. These people want to take charge of the process of making photos in the quest for better results. They want direct control over all aspects of camera function, in particular primary and secondary exposure and focussing variables.

There will, of course, be  snapshooters seeking to upskill, controllers wanting to reduce the complexity of life and a variety of other people who at any given time, find themselves between the two user groups. My thesis is that these  inbetweeners will gravitate one way or the other in due course. If  I am right about this it follows that cameras pitched to the inbetweeners will be perceived as overly complicated by  snapshooters and too limited by  controllers, ultimately appealing to neither group.

Controllers have more explicit and numerous requirements for holding, viewing with and operating a camera. Provided the size and weight are not excessive, a camera designed for controllers will suit snapshooters just fine. This assumes that when a fully automatic shooting mode is set, most of the hard controls are disabled. Such a camera will allow the snapshooter to progress to controller if so desired. The reverse is not true. A camera designed with minimal controls for the snapshooter will not  satisfy a controller and provides no upgrade path for snapshooters wanting to improve their camera work skills.

Phases of camera operation    It is useful to describe four phases of camera operation. Making these phases explicit helps to clarify which tasks need to be completed at each  phase,  what kinds of controls are most appropriate for those tasks and where on the camera they might best be located.

Setup Phase  In this phase the user delves into a menu, or more often a hierarchy of menus, to set the hundreds of variable parameters available. Setup is best conducted at leisure.

Prepare Phase   In the minutes prior to making photos, the user will want to adjust a range of  camera settings for the present environment and photographic assignment. This might be a birthday party indoors with flash, landscape on a sunny day.... and so forth.

Capture Phase  Now the photographer is in the process of taking photos. The controller type camera user will want to quickly evaluate and alter key exposure and focus variables in a time frame of  just a few seconds. This phase places the highest demand on the operational performance of both camera and user.

Review Phase    In this phase captured photos are reviewed. Ergonomic demands are not as intense as in the Capture Phase,  but the process still needs to be streamlined and efficient.

Primary, secondary and tertiary exposure and focussing controls   It is most desirable to explicitly rank the tasks of camera work by their urgency level in the capture phase.  This will help us to better understand what kinds of interface modules (buttons, dials, touch screen etc) might be best for each task, how each module should operate and where it would best be located.

Two key functions which every camera must perform immediately prior to image capture are Exposureand Focus.  Let us look at exposure first.

There are three Primary Exposure Variables. These, as I referred to in the introduction, are

* Time Value (shutter speed) 

* Aperture Vale (f Stop) and

* Speed Value (ISO Setting). 

These three have to be adjusted interdependently, by which I mean if you change one then at least one other value must also alter to maintain correct exposure. I call the selected combination of the three variables the "Firing Solution". For instance  1/15 second @ f16, ISO 100, gives the same exposure as 1/1000sec @ f4, ISO 800.  The first firing solution might be suitable for a tripod mounted landscape shot, the second for hand held telephoto sport/action.  In order to find the optimum firing solution in each photographic situation the photographer can either

a)  Set the camera to fully automatic mode and hope for the best, or

b)  Set the camera to one of the "Scene" modes and continue to hope for the best, or

c)  Take control of the process and make a conscious decision about the firing solution.

In order to implement the third option effectively the user has to learn how to use apertures, shutter speeds and so forth  and the camera has to have the right feature set, with good enough ergonomics, to allow the user to take control of the process.

Primary exposure variables need to be clearly visible in the viewfinder and on the monitor at all times. They are optimally displayed beneath the image preview, not overlaid on the preview which is much more difficult to see clearly.  They must be able to be adjusted very quickly, by feel, while continuously viewing the subject in the viewfinder. This means they need dedicated, direct acting  hard controls, immediately accessible to the right index finger without having to shift grip at all.

Secondary Exposure Variables   These include

*Exposure Compensation

*Program Shift in P Mode

These variables are not primary in the sense that they are not directly involved in the firing solution. However they do need to be adjustable at the same level of immediacy as the primary variables. Again this means dedicated hard controls, directly accessible to the right index finger (preferred) or thumb (second preference). 

Tertiary Exposure Variables  Here we can place a list of parameters which might differ somewhat between users, according to individual preferences in ways of operating a camera.

These might include

*Exposure metering pattern

* Auto Exposure Bracketing

* White Balance

* Link metering to focus area

* Dynamic Range enhancement

* Others depending on preference

These parameters need to be readily accessible in the Prepare Phase of camera use. This is usually best accomplished by allocating them to a "Quick Menu" and/or in some cases  to a physical Drive Mode dial or lever. It should be possible to pull user selected items up from a main menu and relocate them to the Quick Menu.

It should never be necessary to enter a Main Menu to access primary, secondary or tertiary exposure variables. 

Primary focussing controls  These must be adjusted or checked prior to every image capture.

* Start/Lock autofocus  or

* Manual focus

These are maximum priority controls which require dedicated, hard, direct acting interface modules located for immediate operation while continuously viewing the subject in the viewfinder and without having to shift grip with the right or left hand.

By tradition manual focus is controlled by a rotating ring on the lens, operated by the left hand. If the manual focus ring is correctly  located this system works well and divides labour between the right and left hands.  Autofocus, also by tradition, is activated either by half press of the shutter button using the right index finger or by pressing a dedicated button on the rear of the camera with the right thumb. This latter option has the advantage of separating focus from capture, a particular advantage with moving subjects.

Secondary focussing controls  These require fast, easy access but are not usually required prior to every capture.

* Change position/size of active AF area

* Change position/size of active MF area

Direct acting, dedicated, interface modules are required to permit these controls to be made quickly, without interrupting the flow of the capture process.

The user interface system needs to be like that of a motor car in which the driver does not have to think about how to adjust the primary controls such as steering, acceleration and braking.

A good ergonomic case can be made for allocating exposure controls to the right index finger and autofocus controls to the right thumb.

Tertiary focussing controls  Here we can find a range of options and variables which differ with the individual camera. As cameras become more sophisticated and complex this list inevitably grows.  It would  be desirable for items in this group to be user selectable from a main menu and transferred to a Quick Menu. Some could usefully be allocated hard controls, provided those controls were located on the camera in second tier positions, so as not to supplant controls for Capture Phase actions in first tier positions. They include

* Focus type, phase detect/contrast detect

* AF Mode, Single (one shot) continuous,  tracking (predictive)

* AF Area (type),  Single point (selectable), multi (auto select), Multi point clusters, Face detect, etc

* AF tracking mode (focus stays on one target/group or is handed to adjacent target/groups)

* Auto enlarge view with MF activation  ( 2x, 5x, 8x etc)

* Other MF assist (peaking mode or other technology)

* Lens based controls might include AF/MF, Focus distance limiter etc.

These items need to be adjusted in the Prepare phase of camera operation.  Much user frustration will result if they are allowed to languish in a main menu.

Photographs

The two photographs are different views of a mockup camera.  It might look a bit rough but the exact body shape and the precise location in three dimensions of all the interface modules (buttons, dials etc) have been very carefully evolved over many trial versions for optimum functional efficiency.

On picking up the camera the user can feel with the right index finger if it is switched on or off.  The "set and see" type dial on top instantly shows the current Shooting Mode.  The adjacent "set and see"  Drive Mode lever gives a direct reading of the current setting. Both of these can be quickly adjusted in seconds. The handle and thumb rest have been very carefully sculpted  to fit the right hand in relaxed half closed grip as described in the section on functional anatomy. The quartet of interface modules consisting of Shutter Button, Main Control Dial, Button 1 and Button 2, allow Metering, AF start, Change Aperture, Shutter Speed or Program Shift, Change ISO and make the exposure very quickly, with just the index finger, while looking through the viewfinder and without changing grip with either hand. Button 6 allows for AF start/lock without changing grip. The JOG lever #7 allows instant shifting of active AF area size and position in Capture Mode while looking through the viewfinder and without shifting grip with either hand.  All interface modules can be reconfigured to user requirements and all will have Mode Dependent functions. In other words they have one set of functions in, say, Capture Mode and a different set of functions in, say, Review Mode.