[LRflex] Re: 4/3rds system question.

At 26/04/2007, you wrote:
>David,
>
>Your question comes in and it foolows my quest about the link between the
>camera and lens.
>
>Here is the page that started it all:
>
>http://www.four-thirds.org/en/about/standard.html
>
>
>Now, these are diagrams, very informative to me, a little less to you.
>Obviously there is a com between the body and the lens but I believe, tha
>autofocus is managed thru the actuator.


My understanding, Xavier, is that, like all cameras, the actual 
autofocus sensors and "brain" are in the cameras.  However, on some 
cameras, such as the Pentax, the AF is entirely within the camera, 
and when the lens is in focus, it permits the camera to fire.

In fact the manual for Rose's current film-based Pentax advises the 
use of older, MF Pentax lenses for special situations.  For instance, 
if you wish to take a shot of a horse & rider, jumping over an 
obstacle, focus the MF lens on where you expect them to be, and then 
press the shutter release.  The camera will, of course, try to have 
the lens focus itself, but being an MF lens, it cannot.  However, 
when the horse and rider come into view, the instant they are in 
perfect focus, the camera says "OK", and fires the shutter!

Obviously, with the 4/3rds system, there is a more advanced 
communication between the lens and the body.  As we all know, someone 
has figured out a small connector that goes on the lens adapters, 
thus making the Canon AF cameras think they have a Canon AF lens 
installed. Thus, focus confirmation is possible.

You are right, I am sure. Some sort of similar connector should be 
possible for the four-thirds systems, as well.

But, like you, I can find little more than hype and advertising on 
the net.  A copy of the 4/3rds "White Paper" would be really nice!

The reason I asked about the focus confirmation is that other brands, 
such as Pentax, do not require a specific brand of lens to be 
installed, in order for the AF to work.  I was rather hoping that the 
4/3rds models would be like that.  [sigh].

Cheers!
---

David Young,
Logan Lake, CANADA

Wildlife Photographs: http://www.telyt.com/
Personal Web-pages: http://www3.telus.net/~telyt
Stock Photography at: http://tinyurl.com/2amll4

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