I think you're confusing the minimum aperture at which AF will work (f/8 on the EOS 3 and 1 series bodies, f/5.6 on everything else), to the combination (horizontal & vertical) central AF spot that enabled lenses of f/2.8 or faster to focus using that AF point much faster/more accurately. AFAIK, the limit still exists, but a quick Google search implies that it has been improved to more sensors:
http://visual-vacations.com/Photography/canon_1_series_autofocus_custom_func tions.htm Some further scanning seems to imply that newer digital bodies like the 20D have a hybrid center-point sensor that functions as a high precision sensor with f/2.8 or faster lenses, as a normal precision sensor from f/4 to f/5.6, and as a horizontal-line-only sensor for lenses slower than that. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Wednesday, October 04, 2006 2:28 PM > To: [email protected] > Cc: Willem-Jan Markerink > Subject: Re: EOS f2.8 limit for AF-sensors > > > ---- Willem-Jan Markerink <[EMAIL PROTECTED]> wrote: > > Haven't checked this specification for a long time, but with the > > EOS-1(n), there was a limit of f2.8 for the AF-sensor, being > > functional with both vertical and horizontal lines. > > On the PhotoKina, the Canon guys looked at me as if they saw water > > burning, when I mentioned this in the context of the new 70-200/4.0 > > IS....as if there never was such a limit, for more than one > > generation.... > > Yet I don't even recall any big boasting of this limit > being nullified > > with any of the later EOS-1 series.... > > I do recall vaguely that the medium grade models suffered less from > > this, but only by comprimising low-light performance....the center > > sensor of the EOS-1 was much better in that context) > > > > > IIRC, the EOS3, and subsequently, the 1v, had a lower limit > of f8, but I don't know if that carried over to the digital > versions. As far as I know, all other models, Elan7, 30D, > 5D, etc have that f2.8 limitation. > Skip Middleton > * > **** * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
