In article
>On Sun, 23 Mar 1997, Don Atzberger wrote:
>> Plus, for the high-end glass like the 600mm f/4, you can save a pile of
>> cash by buying used Nikkor MF lenses.
>If you don't have trouble with the mount thats true, but yesterday I
>read a letter in german magazine 'Fotografie Draussen' which does not
>throw light on the Nikon service in germany.
>
>This magazin published two stories on the Nikon F5 in one issues, and
>both writers (Fritz Poelking and another guy) praised the new Nikon,
>and ofcourse the possibility to use old MF-lenses.
>
>But now to the published letter. The writer of this letter owns a 600/4.0
>MF IF ED, a TC14 and at least one F4. He writes that the weakest thing
>at the F-mount is the lock of the mount, eg. if he sets up the 600 mm with
>TC and the F4 and he puts some pressure on the F4 the bajonet (sp?) gets
>unlocked. In one case his F4 fell off and the viewfinder was destroyed.
>So he sent the lens and the TC to Nikon but they were not able to replace
>the mount, the didn't even tell him why they are not able to fix the problem.
Hmmm..., the Nikon bayonette and lock are very simple, sturdy, and VERY
easily-repaired... There are only a few parts, easily accessed - and the
design is good, with one possible exception: the actual force that holds
the lens bayonette tight against the camera mounting surface is provided
by a set of strong leaf springs (this provides for tight fit independent
of wear). If a heavy camera (or lens) is attached with a long tube or
converter in place between them, and additional force is applied to
separate the body and lens (or bend them relative to each other), and
if the spring is weakened that pushes the locking pin forward to keep the
lens from rotating (or the pin has been worn down at the end, and is no
longer as long, or as straight-edged), AND the camera or lens is rotated
relative to the other, they could separate without pushing the release
lock... But if one takes even moderate care, this should not occur,
unless some part is defective or worn (unlikely, with even heavy use),
and the defective part is so easily found and replaced... (A mystery...)
Hope This Helps