Autofocus micro-adjust

[Tricky]

Got home too late to really have a play with my new 7D, so decided to spend an hour (it soon became 2 hours) micro-adjusting the AF on my lenses. My old 40D didn't have this facility and I had long suspected that at least one was a little bit out.

I used the information and test charts provided here and here. My calibration findings were as follows:

[ATABLE]24-105| -5
Siggy 30mm | -8
60mm macro | -3
10-22 | -4
10-17 Fishy | -4
70-200 | -2
700-200 + 1.4x |-4[/ATABLE]
[not quite sure how you use the table facility on AP!]
Mod edit: fixed table ... use | as the column separator http://www.ausphotography.net.au/for...ad.php?t=39799

I think this probably tells me that my 7D has a small tendency towards 'minus'! Perhaps -4 is the camera, whilst the difference is each lens. These aren't big differences, well within manufacturing tolerances, and indeed illustrate the 'raison d'etre' for the micro-adjust facility.

I also noticed that on zoom lenses, the ideal calibration adjustment varied depending on the focal length. On the 70-200, the adjustment was -2 at both ends (70mm and 200mm), but 0 at around 135mm.

With the 24-105, the adjustment was around -5 from 35mm to 90mm, but then -6 at 105mm and 0 at 24mm! I suspect the depth of field at 24mm is fairly deep, so less critical... I left it at -5 as a compromise.

Anyway, I'll double-check the findings on 'real' subjects when I actually get a chance to go out and take some pictures!