>>I called Canon service and they said it is possible to >>adjust the AF (for different lenses) so I quess I need >>to send the camera and lens in. > >Hmmm. again lens + camera combo. This is very similar to the question I >posted earlier about metering problems with certain lens. That was also >acknowledged by Canon. > >So, if AF also happens TTL and camera sends commands to the lens motor for >adjusting focus (at least this is what I've been led to understand by >Canon), then how can the camera be adjusted to focus with some lenses? What >would then happen to AF with other lenses? If nothing, then why is that one >lens affected?
Good questions. I think they (and I) didn't necessarily mean individual lenses or lens models. Perhaps they make adjustments for lens length (mm) and/or the maximum aperture (f-value), either together or separately. I wouldn't be surpriced though even if they had some means to adjust AF for some (Canon) lens model (kind of exceptions for the general rules) but this is just my speculation, nothing more. The angle (f-value) and direction (lens mm) might have some effect on the AF mechanism adjustments just like it probably has on the exposure system and adjustments. I have only two lenses with max aperture worse than f4, the 28-135 and the 100-400, but I have not critically checked the 28-135 zoom focusing. So perhaps my EOS-3 needs adjustment for slow lenses? But, at this point this is just speculation since I don't know if the problem was in my test method/implementation or if it was in the camera/lens operation. I'll tell you more if there is something to tell (may take some weeks though). BTW. I was using a second-hand-bought '3' which was fired only some 1300 times (after the previous owner had used it for one year or two). Like new condition but I don't know the history of it. Vesa _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
