Why does my lens on Nikon D60 keeps dismounting?

I have two lenses, one is working properly (nikkor 35mm), but the second one (Tamron 28-300) likes to disconnect from the body. I mean it is perfect mounted on the body, but the camera tells me on the screen that it has dismounted ( it shows that -f- flashing sign or something).

What could be the problem?

Has the Tamron ever worked properly? If not, then it may be a lens designed for a Canon mount.

If it fits the way its supposed to (ie, proper lock with no wiggling) then the electrical contacts on the lens may be dirty and in need of a cleaning. Tamron lenses carry a 6 year warranty so if it is a lens defect you should be covered if you bought the lens from a proper retailer.

It's not dismounted. The "F" or "Fee" error message means that you need to rotate the aperture ring to the smallest setting (largest number) and move the ring lock on the lens. The "G" series Nikon lenses don't have an aperture ring, so you'll never see that error.

http://support.nikonusa.com/...ra-mean%3F