Shocking insight: AF is not a closed feedback loop!

Started Jul 18, 2003 | Discussions thread
DavidP Forum Pro • Posts: 29,088
but how do it know?

As Mishkin described it, he said the body tells the lens "go 20 steps thata way", and the lens goes 20 steps that away, and it's done. No feedback at all? No double-check? As in, "OK, I went 20 steps, now waddya think, big boy?"

If it's only a single step, the body would have to know what size steps the lens takes, right? That would mean the lens has to know that info, and tell it to the body somehow, right?

Jason Hutchinson wrote:

Loop stability is the most likely one, but what about the response
time of the older motors? They're clearly not designed as well as
modern USM motors for the small repetitive motions that'd be
required for that. Who knows.

-- hide signature --

The Lowest Paid Concert Photographer Around
http://www.neonlightsimaging.com/artshow/final.htm
Photography -- just another word for compromise

'Since we can't keep crime in check, why don't we legalize it and tax it out of business?' -- Will Rogers

Post (hide subjects) Posted by
(unknown member)
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow