Interesting article and as you say probably throws a lot of light onto AF issues.

Part of the problem is that I think many people take auto to mean infallible and are bemused when things go a bit astray. Doubtless it is possible to build an AF camera and lenses that, assuming the target has sufficient contrast etc, will hit the focus spot on every time - I'm can't see too many 'togs paying the sort of price that would come with it......

I do wonder if the demand (whose?) for ever faster AF hasn't added to the issue. The faster you run AF motors and the shorter the the turn required to focus the more issues like backlash and overrun are going to be proportionally exaggerated unless they are well controlled.

I'd have to agree re pixel peeping. One of the first things I noticed (and fretted about...

) when I got my 20D is how much softer the images looked. Then it was explained to me that yes they will look softer because the 20D has over double the pixel count and that at any magnification on screen, and especially actual pixels, I may be looking at the same number of pixels but from a much smaller part of the image - much the same as looking at a 6x4 enprint from a foot away then doing the same with a 20x16...

These days I generally assess images at no more than 50% size as this gives a far better impression of acceptable sharpness, mind whether that would still hold true for a 12meg I'm not sure... I think it ought to though, as long as the on screen image is viewed from a suitable distance and looks acceptably sharp then it really should be OK at print size....