Re: Quote of the Day

[Bruce Rubenstein]

Throat diameter is just one thing. What Canon did was to system engineer 
an entire SLR system from a fresh start. This means that folks sat down, 
figured out what they wanted the system to do and then figured out the 
best way to do it. They determined that electronic control of the lens 
was best for what they wanted. Once they knew the largest diameter they 
would probably ever need to optics, they included all the electrical 
contacts they might need. From this, they were able to figure out what 
the lens mount diameter had to be. (Standard system engineering practice.)
Pentax didn't keep cobbling their mount, they changed from screw to K, 
with no backwards mechanical compatibility to use a K mount lens on a 
screw mount body. Pentax and Nikon have been enhancing the 
control/command, lens/body interface to add new functions. The problem 
is that they've have made a series of changes, sometimes taking 
different directions (Nikon AIS). They are classic "evolved" systems, 
rather than "engineered" ones.

BR

[EMAIL PROTECTED] wrote:

What was it about the old Canon mount?
Too narrow?  Too far from (or too near to)
the film plane?  Have Nikon and Pentax been
able to keep cobbling along because their mount
dimensions were more generous?  Somewhere this
must have been written about, but I've never
seen an article or discussion.
-Lon