--- Ken Lin <[EMAIL PROTECTED]> wrote: > I'll try, but with the caveat that it's a (logical, I hope) > speculation on > my part.... > > Given the same AF motor and general construction, AF speed would have > to be > slowed down if one lens is slower (darker) than the other
But now you are not comparing two identical lenses anymore. The claim was that by improving some firmware in a lens THIS very lens can become faster. > , else the > darker > image from the slower lens will likely cause overshoot and hunting as > the AF > sensor in the camera struggles to snap the image into focus, But that's a problem of the AF algorithm and not some firmware in the lens, right? > while a > brighter image from an optically faster lens will produce an image > that is > easier for the AF sensor in the camera to lock on to, allowing Canon > to > speed up the AF motor speed for the brighter lens. But that is all done in the camera, right? My assumption is that the lens tells the camera its max aparture, the current position (AF distance) which is updated at small discrete points while the lens is zooming, etc. So the camera knows at what position the lens is and how fast the lens is zooming. The later can easily be calculated by the current and last position divided by the time between these to updates. If this assumption is right then I do not see how some firmware in a lens does make a difference. Has anybody any idea what information the lens and camera actually exchange? Robert __________________________________________________ Do You Yahoo!? Send your FREE holiday greetings online! http://greetings.yahoo.com * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
