I have the AF version. Without the TC, you should be able to use program mode M and A. (note that you have to move the aperture yourself but it should register with the camera- I think - been a while since I had a D90 in hand.)

With the TC that really depends - what maker and model info is the TC? You can not use Nikon TCs (newer at least) with any Tokina lens. Tamron & Kinko (same thing really) both work.

yes, i guess the question is, do you have the problem without the tc?

I have a nikon 300 2.8G and a tc20eiii and it is only good from f8. i'm guessing your setup maybe even less capable.

as for metering, do you have to lock the lens on the widest aperture, then control from camera?

My understanding: D90 will mount Ai and Ais lenses. If like me you have a TC200/TC201 Nikon teleconverter (old manual teleconverter that gives interface like Ai/AiS) the camera will not meter. I believe you mount the lens camera in manual mode only and guesstimate exposure. Adjust aperture on lens and shutter on camera and take shot after shot until it is good. If it is an AF teleconverter like the Kenko Pro 300 it should work fine. Maybe contacts not lined up, gently wiggle it to make sure it's mounted correctly? I assume you've tested the lens without the TC and that is fine.

Does the lens mount have any electronic contacts on it?

Hi
I have a Nikon D90 and recently bought a Tokina 300 2.8 at-x SD from ebay with a 2x tc.
I know the lens will not auto focus but this lens does not let me use any other mode apart from the "M" mode and with that as well I do not get an option of F.
Can anyone please guide me? Please tell me how to overcome this.
I have up on google but there is not much info available on this.