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.