> I don't think I have this problem, but does it occur if one changes > the zoom without refocusing, or does it happen even if one refocuses > after zooming the lens? None of my lenses, all Canon, one L series, > seem to have the ability to change the "back focus." (As described in Karl mentioned digital users being "touchy" Googling around on the "10D focus problem" sure highlights this! The number of replies insulting people who have the temerity to suggest that *thier* 10D has a problem simply because the respondant's apparently does not is amazing. It's almost evangelical ;o) Testing auto-focus on your own camera is a doddle: but what is "wrong" anyway? Who said an AF sensor should actually lock on the correct distance anyway? 1) Maybe research has shown that it's nasy to have OOF objects in front of the subject so the nice people at Canon have weighted focus towards a slightly nearer bias? It's to help you take better pictures after all? 2) So what if the viefinder image does not correspond: rendering MF all but unusable. You should be using AF anyway. Digital is superior to everything including the best precision of a discerning human eye. MF just confuses people - hands them back a link to the good old days when people had to learn to be able to judge focus while framing and timing a shot ... Anyway: I enjoyed a simple test listed at: Bob Atkins: http://www.photo.net/learn/focustest/ Some of the caveats to this centre on it being unfair: I prefer to use a steel "flea comb" supported at an angle. Bizarely on my old film cameras AF and MF both seem to agree with the result on film: the camera focusses on the sensor. Actually AF is slightly less reliable - particularly for a second press when it insists on focussing somewhere else from where it started ;o) I don't think the 10D problem is all hysteria: enough reliable people have reported it even if perhaps a large fraction may not have spotted it without the internet hoo-hah. Bob
