> > > > >> >Has anyone read that the 1D Auto Focuses at apertures up to f/8 as > > >> >opposed to f/5.6? > > >> > > >> No. Autofocus is only operational at f5.6 and faster. > > > > > >Wait a minute. I thought it had the autofocus of the 1V, in which the > > >center AF point operates at f/8!? This is NOT true? > > > > > >As far as I can see, there is no mention of f8 focusing capability in > >either the EOS 1D brochure or the other technical data we have. The > >implication is that all seven of the central focusing sensors are the > >same, unlike the EOS 3 and EOS 1V which have a different centre sensor. > > > >However, it is possible that this is an omission from the data and that > >the camera will focus at f8. > > > > > >ROBERT SCOTT > >EOS magazine > > Maybe the 1.3x factor has something to do with this? > > Since the image (and AF points and AF area likewise) is > enlarged by that amount maybe the AF accuracy at f8 is > no more "good enough". Or just can't be done for the > same reason. > > Just quessing. > > Vesa
Hey Vesa, Good guess IMO! Given the required acuracy needed to lock and track AF the 1.3x factor may be the key limiting factor here as it is in other EOS bodies. At some point, for reliable, repeatable focusing the AF sensors will reach the point where the anglular resolution is too small and they cannot provide enough accuracy to provide a reasonable level of focus for a given level of magnification reliably. Hey Canon, if you are reading this message here is a free bit of creative thinking. I don't know if Canon is working on doing this or not but seeing that it appears that the EOS 3, 1v and 1d all use the same AF box in the bottom of the body. And given that the AF sensor looks an awful lot like a CCD or CMOS array, and that they are now using real lenses to focus the incoming light on the sensor array, and the fact that they have a lot more CPU cycles available now with the faster RISC processor, couldn't Canon use a differential technique in real time to effectively broaden tremendously the AF sensor's baseline and improve the AF performance under these conditions? This might only allow for a single central AF point given the time requirements and the number of CPU clock cycles they have but it should work perfectly and improve the lens speed issues with respects to AF and lens aperture. Regards, Chip Louie > * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
