When I use my Tamron Adaptall 2 60-300mm F3.8-5.6 MF lens with the Tamron 2x TC on either my D200 or D300, in the non-CPU lens settings, do I set the focal length at 300mm or 600mm, and the max aperture at 3.8 or something else? How is the non-CPU setting affecting the function of the camera, i.e. exposure etc? This set-up works great, in good light, on a tri-pod shooting birds at the feeder in the back yard, especially in live-view on the D300. Thanks.