I just noticed that the lens mount on my new AF-S lenses has 10 CPU contacts, 5 more than the conventional Nikkor AF lens. Some of those must be attributable to AF-S control channels. But the F100 has 8 contacts while the N90s has only 7. So at least 2 of these channels are not accessible to the current generation of cameras. Perhaps some unannounced function planned to work with a future generation of camera? Does anyone know what each of the contacts do?

-- chuck fan (chaohui@msn.com), February 10, 2000

Answers

Certain Canon lens has more contacts than the body - they are designed to mate with the extra contacts on the EF 1.4x and 2x extenders. The extenders have the usual number of contacts on their 'camera-side' lens mount. The additional contacts may well be there for a similar reason as the additional contacts on the EF lenses - so that the true aperture can be displayed on the camera.

-- Stuart Mitchell (stuart@realogy.com), February 10, 2000.

Nikon designs cameras to work with the features they know their lenses will have 5 years in the future.

Check the 80-400 VR data sheet. As I recall it won't work with the N90 and only works with F100, F80 and F5.

-- ken rockwell (ken@powerinter.net), April 05, 2000.