Nikon 85mm PC MICRO operation with D3

Hello:

I've read about this combo and all people confirm that is amazing... but I've a question.

What is the operation, or workflow, to shot with this lens?

There are a extrange button to "stopdown" the aperture...but I don't understand what is that.

The focusing is manual, but...

• I can meter light with D3?

• I can fix the aperture from my D3 or must be defined in the lens?

• I must fix the same aperture in camera and lens manually or exist any comunication between both?

Thanks in advance.