Camera Labs

Hi all
So anyone know how the aperture control mechanically works on the D90 or other Nikon DSLR's?
On a G series with no aperture ring they say the camera controls the aperture, but is it all actually happening in the lens how much the diaphragm opens or the camera only moving the aperture lever a predetermined amount to open the diaphragm to the correct size?
I think i just read that Nikon have introduced an all electronic diaphragm now, so i guess theres no mechanical connection to the body with those, only electrical contacts.

I notice on my lenses that do have an aperture ring that the rear lever can travel its full distance and the diaphragm will open fully then drop back to the correct aperture size as decided by the ring setting.
So with these i guess the actual connecting lever in the camera will go the full min / max amount of travel and not stop along the way.

Hope that sort of make sense what im on about?!

Afaik only the PC-E tilt/shift lenses from Nikon have an electronically activated aperture. With G lenses the aperture lever on the body determines how far the lens closes. The D-lenses had the aperture ring to limit the amount of "closure" on the aperture regardless of how far the lever was released. So the tolerances of the D-lens determined how preceise the aperture was set. With a G-lens the tolerance of the lever plus the tolerance of the activator in the body determine how precise the aperture is set.

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

So i guess the camera senses what lens is attached and changes the way it controls the aperture lever.