Rear dials

 

In a previous post on front dials I wrote that these were often placed in a variety of different places with an apparently wanton disregard for human functional anatomy. Unfortunately I can say the same thing about rear dials.

Just as the optimum placement of front dials can be studied from a functional anatomy perspective so can rear dials. In the previous post I expressed the view that there is an optimum type and location of thumb support. With this in place it becomes possible to explore the optimum placement of a rear dial. Just to clarify I am referring here to mode dependent control dials, the function of which depends on the current operating mode.

Whether the rear dial is the only mode dependent dial or is paired with a front dial makes no difference to it's optimum position on the camera.

I have used cameras and built mockups with rear dials just about everywhere on the top and rear section of the body. There is little to be gained by analysing all the poor or suboptimal rear dial placements. I will just describe what I regard as the optimal position, which is:

On the thumb support as shown in the photographs. If the thumb support has the optimum projection rearwards, is designed to be wide enough and is the optimum shape then a rear dial can be fitted very nicely into the optimal position on the support.

This is my medium sized full featured mockup illustrating optimal configuration of the thumb support and adjacent UIM's. Here the thumb is in basic hold position in capture phase of use. This is the most relaxed/strong position for the thumb and is where the thumb spends most of it's time. The AF start button which can be seen in the photo below can be pressed by flexing the interphalangeal joint  of the thumb.

 

The thumb is free to move from side to side. Here it has moved to the right side to operate the control dial. The camera is still held securely by the fingers wrapped around the handle at the front. I have not forgotten the left hand but in these photos it was being used to press the shutter of the taking camera. In use a real camera body/lens would be supported by the left hand, making the right hand's job easier.

 

Now the thumb has moved to the left to operate the JOG lever. This lever is used to directly control position of the active AF area. The thumb has freedom to move up/down left/right to operate the JOG lever.  This means the AF area position can be quickly moved at will while looking through the EVF and without having to shift grip with either hand.

 

The thinking and the practicality of this is as follows:

The thumb should be in the relaxed/strong position for holding the camera while previewing and while making photos. The thumb spends most of it's time in this position with occasional excursions to operate the dial and/or other UIM's. If the handle and body are well shaped then:

Without having to change position of the index finger or the other three fingers of the right hand, the thumb can:

* Move from side to side diagonally across the upper rear of the camera and

* It can also flex at the interphalangeal joint, pressing the distal pad into the top part of the camera back.

The optimum disposition of user interface modules which encourage the thumb to efficiently hold and operate the device is shown in the photos.

Here is a Panasonic FZ200. This camera has reasonably good ergonomics but could be improved in several ways.  Here the thumb has been swung to the right from it's basic position to show the location of the rear dial.  The rear dial would be directly in front of the distal thumb pad in basic hold position. The problem with this arrangement is that the thumb support must be quite small  in order to enable the thumb to swing from side to side as it operates the rear dial. Therefore the thumb support is less effective than it could easily be with a different detail design in this part of the camera.