Front control dials

Rest area for goats, Barrier Highway New South Wales.
All right it's not really for the goats but they have taken up residence.

 

Some cameras have a front dial, some a rear dial, some have both. I am referring here to control dials (Command dials in Nikon speak) the function of which is mode dependent and which usually complement a Mode Dial on modern cameras. However hybrid traditional cameras with no Mode Dial often have one or more control dials too. There is always some task which a control dial can perform.

The camera which ignited my interest in ergonomics was the Panasonic G1. One of the several reasons for my frustration with this camera was the unsatisfactory location of the front dial. It was positioned near the top of the handle, in front of and below the shutter button such that with the right hand in normal hold position the third finger lay over the dial. As a result I had to change grip every time I wanted to use the dial. As this dial is the second most often used UIM after the shutter button, I found that to be a very big ergonomic problem. It was also a completely un-necessary one since locating the dial optimally would have been just as easy to fabricate and cost no more.

Over the years I have used many cameras and am regularly astounded by the apparently whimsical fashion in which the front dials of various models are scattered about the upper front region of the body or handle with wanton disregard for human functional anatomy.

Canon EOS 60D showing typical Canon DSLR layout. The hand posture is good but the control dial could be a bit closer to the shutter button and re-oriented to better follow the natural action of the finger. ISO is a primary exposure parameter requiring adjustment in Capture Phase. The ISO button needs to be closer to the shutter button and control dial and shaped so it can easily be located by feel. Some Canon cameras, paradoxically those aimed at the entry level have an ISO button which is easier to reach.

Consider the motor car. I can get aboard almost any passenger car and drive it safely without having to look at the main controls. If the brake and accelerator pedals and other essential controls were not predictably located the road toll would be horrendous. Cars have evolved such that their control systems are well designed in the ergonomic sense. Cameras don't usually kill people so the ergonomic imperative is less intense. But it is still there and the ergonomic muddle of many current camera models will ensure plenty of customers who might be aware that there is some kind of issue with their camera's usability but can't find the words to identify the reason for this.

Is there, like the motor car, a "right" or "best" or at least "most effective" location for the front dial ? Some people might say that ergonomics is all subjective but so is image quality. Yes at the end of the day these things are subjective. But they are also capable of analysis. There is a discoverable and measurable reason why one camera has better image quality than another. Likewise there are discoverable and describable reasons one camera is nicer to operate than another. Ergonomic characteristics can be identified and compared as to their fit with functional anatomy.

Samsung NX10. Although quite small this camera is comfortable to hold. The control dial is well positioned just behind the shutter button and at the same height. It could be angled a bit to better follow the finger.

I have been researching this for several years and I say yes there is a most effective location for the front dial. This follows from an ergonomic analysis of functional anatomy. Allow me to explain.

Those who follow this blog will recall that in my previous post I proposed that there is a most effective design for the handle, that being the inverted L type. I said that one of the advantages of this handle type is the platform it provides for the placement of user interface modules (UIM's: buttons, dials etc) adjacent to the shutter button. One of those UIM's is the front dial.

This mockup is the same size as the Samsung above but has a larger inverted L shaped handle and quad control system on top. It is difficult to convey in photos but this feels more secure and substantial than the Samsung above. 

Please follow my reasoning I propose that the basic ready to operate hold position should approximate closely to the half closed relaxed hand posture which I have been discussing in recent posts. This position is stable and strong yet relaxed. In this position the distal pad of the right index finger will lie naturally on the shutter button. There is substantial separation between the thumb and index finger but very little separation between the index and third fingers. The index finger spends most of it's time on the shutter button with brief excursions to the control dial and other nearby UIM's. It is preferable therefore to locate the shutter button forward and the control dial behind the shutter button. It is also desirable to place the top of the shutter button and the top of the control dial at the same height relative to the pad of the index finger as it moves side to side on a forward tilted plane from one to the other. The optimum distance between the two is the minimum distance which will prevent accidental activation of either. In my work with mockups I have found the optimum distance between the center of the shutter button and the centerline of the control dial to be 12-13mm. The optimum orientation of the control dial is that which follows the line of movement of the right index finger. This means the attitude of the dial will usually be tilted in two planes. The shutter button and control dial both sit about 4mm elevated from the top deck so the index finger clears the two buttons which make up the quad control group. Read more about this in a post coming soon.

When the reader looks at photos of my mockups, you might think that the buttons and dials are just placed in approximate positions. In fact I adjust and re adjust the shape of the body and handle and the precise location of all the buttons and dials in 3 dimensions until they are in exactly the optimum positions. A single millimeter here or there makes a significant difference.

Conclusion Photographers mostly become accustomed to the camera which they own. Even if it has suboptimal ergonomics users find workarounds for most operations. They will often declare that they "like" their chosen camera and may reject a different one even if it has in fact a much better user interface. I suspect the usual reason for this is change fatigue. I am suffering from this myself at the moment. Our family has just bought a Microsoft Surface Pro 2 and we are struggling to adapt to the new UI. I am sure that in due course it will prove itself but the learning curve is steep.

Photographers may initially reject the control dial position which I advocate if they are unaccustomed to it. In the long run however a camera with optimal ergonomics will be more enjoyable to use than one which is not quite right.