Hi guys, just got my new D90 and it's really killing me that my Tamron 17-50 doesn't mount on this new baby. I previously owned a D5000 and the Tamron had no problem. Now with the D90, 95% of the time I will get the F mounting error. I've tried cleaning the connector using eraser but still no help. Is anyone experiencing the same problem? This is really frustrating since I love the Tamron

This happened to me with the same camera and lens, but only about 20% of the time, and I didn't get an error, just wouldn't auto focus. I have put many other lenses on the body and never had one problem, so for me it was just that Tamron 17-50 f/2.8 (new version with built in motor) that didn't work properly.

Never had such problems with my D90 and two Sigma lenses (70-200 2.8 II & 30 1.4)

If it gives F-- on the control panel and in the viewfinder, that means it can't communicate with the CPU in the lens to read out the focal length and aperture. It may need a trip to Tamron for service, you may want to see what they say.

My D90 works perfectly with 3rd party lenses. To be honest, I'm not sure the camera has ever had a Nikon lens mounted.

There is a bit of play between locking and won't turn anymore. Try rotating the lens in that little bit of "play" area. It will probably clear the problem up. It worked for the D80 and Sigma 70-200 f2.8

No problems ever with my D90 and various Tamrons and Sigmas.

My D60 didn't like my Tamron 70-200, but my D2x loved it. Hoping my new D300 won't play favorites when it arrives tomorrow.

I followed runamuck's suggestion and it did cure the problem. What a relief, I was ready to send the Tamron for service. Thx guys.

Glad to be of help.