Discovering Camera Ergonomics Part 9 Capture Phase controls

Two fully featured current model cameras from the same maker. I own both and use them regularly. The one on the right works much better ergonomically. Everything is better. The handle shape, thumb support, rear dial position and configuration, cursor button module (4 way controller) design, button position and design, Focus Mode lever position and more.  

There are four phases of camera use   Setup, Prepare, Capture and Review. This has implications for the design and location of hard controls on the camera body, lens barrel and lens.

There is a hierarchy  by degree of urgency of  tasks to be completed in each Phase.

Capture Phase  tasks have the highest urgency level. Therefore controls for Capture Phase are optimally located in the highest value camera real estate locations.  

* The right hand has the same relationship to the camera in landscape or portrait orientation. It is also substantially the same whether the camera is held to the eye or out in front for monitor viewing or above the head with monitor viewing. For waist level and lower viewing a different  holding position of the right hand is required.

* The left hand has a more complex relationship with the camera. There are four basic positions, landscape orientation hand over/under and portrait orientation hand over/under. Variations will be required when the camera is held above or below eye level.

My analysis shows that Capture Phase tasks are best carried out by the right index finger and thumb and the fingers of the left hand acting together for simultaneous supporting and operating duties.

In Part 5 of this series ‘Discovering Camera Ergonomics’ I described a specification for Capture Phase requirements. In summary this is: All primary and secondary focus and exposure parameters can be efficiently adjusted without taking the eye from the viewfinder and without shifting grip with either hand’.

How not to do it. Canon G1X. The white arrow points to a front dial, hiding behind the middle finger. To operate that dial the user has to release grip with the right hand, shift the hand downwards, work the dial and return the hand to the normal position. 

Let us see how this can be accomplished.

The Right index finger  is the only one allocated entirely to controlling duties with no gripping  role.  It is therefore universally tasked with pressing the shutter button. But there is no agreement at all among users or manufacturers as to what other tasks should optimally be allocated to the index finger. 

When I look at existing cameras, I see so many different types and locations of user interface modules (UIM) for the right index finger that I find little useful in the way of themes to discuss.

So I offer what I have worked out to be an optimal configuration with my reasoning.

As shown in the photos, this is the ‘quad control set’ on the top plate of an inverted L type handle.

The index finger can move from side to side at the carpo-metacarpal joint over a  range of about 15- 20mm for an old guy like me and a bit more for younger, more supple people. The finger wants to stay in the same plane (relative to the other fingers) while doing this.

The index finger can also flex/extend at the carpo/metacarpal and interphalangeal joints over a greater range.

The inverted L handle plus quad control set make optimal use of these anatomical capabilities.

In my mockups I put the shutter button in front of the control dial. After sculpting the shape I let my fingers lay where they wish. I figure I will want my finger on the shutter button most of the time so I put that button where the index finger most wants to be. That is quite close to the middle finger, not separated from it as required by many camera handle implementations.

The mode dependent control dial goes in the secondary (rear) location with its center 12-13mm behind the center of the shutter button. That is closer than most cameras provide.  However I find that degree of separation facilitates efficient operation but still prevents inadvertent operation of either module.

The shutter button is oval in shape to accommodate longer and shorter fingers.

Both shutter button and control dial are raised  4mm above the top plate of the camera and are rough textured for easy location by feel.

The two buttons each with user allocated function sit lower so they will not be bumped accidentally and each is also prominently textured on the top surface (the mockups use Phillips head screws) for ease of operation by feel.

I note that many cameras feature smooth, rounded buttons which I suppose are designed to look sleek or something like that but they are difficult to locate by feel and are therefore an impediment to efficient operation. 

The index finger can easily and quickly move from any of the quad control set modules to any other by feel, without moving any other finger.

It can therefore carry out the following tasks:  Start/lock autofocus, Start/lock auto exposure, change aperture or shutter speed (depends on Mode Dial setting), change ISO (or other parameter as desired), change exposure compensation (or other parameter as desired).

Here is another example of how not to do it. Canon G1X again. There is no proper thumb support. There is a video button right where the thumb support should be. Consequently the user is forever accidentally starting video clips, while failing to hold the device securely.

The Right thumb  has both gripping and controlling duties. It needs to maintain opposition (refer back to Part 6 of this series) and simultaneously work several user interface modules.

The thumb can swing side to side by articulation at the carpo-metacarpal joint. It can also flex a small amount at the interphalangeal joints without unduly disrupting opposition.

If we look at a range of existing cameras we will quickly see there is no general agreement about what types of UIM should be worked by the thumb nor precisely where they should be located. In particular we see rear dials scattered about in the approximate vicinity of the thumb in what appears to be random fashion.  So rather than trying to discuss the merits or otherwise of various existing arrangements I present a configuration which I have found to be optimal.

This is based on a substantial diagonal type thumb support with a rear dial embedded in the thumb support and a JOG type lever (a.k.a. Joystick) to the left of the thumb.  If they are optimally located and shaped , with strong haptic qualities, both these UIMs are easily reached and operated using the ability of the thumb to move side to side and be pressed inward into the body of the camera without disrupting grip.

There is also the possibility to locate a small AF-ON button beneath the ball of the right thumb, activated by flexing the distal interphalangeal joint, as seen on some high spec Canon DSLRs.

Now the thumb can: hold the camera securely while shooting, quickly move active autofocus area anywhere on the frame, start/lock AF separately from AE if desired, control whatever parameter has been allocated to the rear dial.

Panasonic FZ1000. Good design of cursor buttons (4 Way controller) and adjacent buttons. The 4 way controller is easy to locate and operate by feel. Look at the rear dial. It is well shaped and positioned so it is easy to operate by swinging the thumb to the right without bending. The cutaway thumb support is a bit odd, they should fill in the shape with the next version.

Push-click-dial function  There already exists well tested and proven technology for obtaining two functions from each of the front and rear (mode dependent) dials. This is push-click. Push the dial once until it clicks, it performs one function. Push the dial in again until it clicks and it performs an alternative function. This works just fine on several Panasonic cameras owned by me.

It should be feasible to design a Main mode Dial with a ‘K’ (or whatever) setting such that with the Mode Dial on this setting the shooting mode could be changed directly with one of the front or rear dials after push-click.

This would allow the user to upgrade  Mode switching, usually a Prepare Phase function requiring two fingers and release of the right hand grip to access the dial, to become a Capture Phase action, without shifting position of either hand.

Panasonic FZ300. How not to do it. Zoom and focus controls on the left side of the lens barrel. These are awkward to locate by feel in landscape orientation with still or video capture, and impossible with portrait orientation. 

The Left hand  as indicated above has a complex relationship with the physical structure of the camera body, lens barrel and lens. The left hand and fingers work together as a unit engaged simultaneously in  support, gripping and controlling duties.

The only kind of user interface module which the left hand can always find by touch and work properly in landscape/portrait orientation, hand over/under and camera at/above/below eye level is a full circumferential ring with prominent grooves, lands or serrations all the way around. 

This type of module is used for zoom and manual focus duties.

Some cameras/lenses also use a ring type control for setting aperture. However I regard this as a legacy feature which my motion studies have shown to be ergonomically less efficient than a well configured control (command in Nikon speak) dial. 

Fixed UIMs such as buttons, dials, levers, switches and similar on the lens barrel are suitable for 

Prepare Phase adjustments when the camera can be lowered from the eye and the buttons etc. inspected visually for adjustment. Parameters which might find themselves here could include OIS (IS, VR), Stabiliser mode, AF/MF, Focus limiter, Macro setting.

Summary With good ergonomic design  my ergonomic specification for Capture Phase is readily met, allowing the camera to be driven like a sports car, controlled by the right index finger and thumb and the left hand and fingers acting together.

Next: Controls for Setup, Prepare and Review Phases