Hi Ken,
As a lawyer, I am not qualified to discuss about this subject to the same
extent of, for instance, an engineer. However, as a classic cars
admirer/owner who tries to understand and service them by myself, I like to
improve my knowledge concerning these aspects a mechanical machine.
I think your statement is correct, about adding couplings not necessarily
meaning loosing power. However, at least in my practical experience, even
without any angular displacement, as you said, a coupling can cause a power
loss or, at least, an efficiency drop, if there is any kind of "play."
I know these circumstances only produce an infinitesimal loss, as you
appropriately pointed, but even an infinitesimal loss may be enough to
determine a negative effect on a AF motor, as it probably will be no more
than a tiny electrical motor. Of course this effect can be minimized by the
use of a larger motor or some kind reduction gear or box, that would allow
it to deal with the added stress, although at a slower pace.
I'm not sure, but I think even the size of a shaft can cause a power loss,
specially if it's not precisely balanced. Could you tell me anything about
this? Anyway, in this aspect --- having a shaft or axle --- I think a AF
system is similar to a car transmission. Am I wrong? In what way?
I guess the car analogy could be developed further. Think about it:
switching to manual focus on a AF body produces the same effect of
depressing the clutch pedal on a manual transmission car... One more thing
that I would like to know is that if by doing so the electrical current
going to the AF motor is also cut... Any idea/information?
I hope my thinking is clear enough, in spite of my lack of ability with the
correct technical terms.
Best,
Eduardo.
-
This message is from the Pentax-Discuss Mail List. To unsubscribe,
go to http://www.pdml.net and follow the directions. Don't forget to
visit the Pentax Users' Gallery at http://pug.komkon.org .
