Curious close-focus

[GetBusyLiving]

I have just purchased a used Olympus 17mm f1.8. This model has a manual focus clutch on it and I've noticed that if I set it manually to closest focus, I am about 8" away from the subject, but if I let the camera auto-focus it can get down to about four inches. It's not any sort of problem, I'm just curious as to why the discrepancy.

 

[woof woof]

I have had that lens but I never noticed this, I suppose it's just how it is... but I think it's usually the other way around. I have known lenses focus closer with MF than AF and in fact I can't think of anytime I've seen a lens focus closer with AF than with MF.