Appreciate the reply. However, I was not able to access the link in the reply; apparently it is invalid. I do understand the concept that what changes is the position of the focusing stepper motor. To me it makes sense that a given change in position of the stepper motor corresponds to a small change in focus position for objects nearby and to a large change for objects in the distance. That would be SIMILAR to saying a certain amount of change in position of the stepper motor corresponds to a certain percentage change in the focus distance. The reason I have a question is that as far as I know with chdk one specifies a change in focus distance in millimeter. That is an absolute change, not a percentage change. It is that discrepancy that I do not understand and that prompted my question. Again I thank you and would appreciate your kind reply.
