[Brightcolours]

And I "heard once" Sigma is manufacturing Nikon OEM lenses

That is not true though. Tamron had some involvement in the past with one or two lenses.

and Tokina makes Canon lenses.

That is an even sillier "rumor". Tokina makes some Pentax lenses. Parent company Hoya is a big optical glass manufacturer, they might supply some raw materials to Nikon and Canon, but Nikon and Canon make their own glass in different formulations too.

Where' smoke there is or was fire but I have not that insight into those factory deals where competitors turn out to be colleagues.



Anyway, I could use the Sigma adjustment, but then it's only for this camera. For D800 / D7000 / D7100 I set camera AFA values of -10 / -4 / +2. Funny thing is, D7100 recognizes a "24-105 F4” but is pairing it to the lens number of the 105/2.8. If I delete the AFA setting for the 105 in my D800 and mount the Sigma to it, this body also recognizes "24-105 F4”. Until I mount the 105, than both lenses are treated like one.


Weird.


The other two Sigmas of my lens stock are recognized without probs, but I don't own a Nikon 35/1.4 or 18-35/1.8 from Nikon. At the moment my explanation remains as "kind of firmware bug".