AF-S Nikkor 24-70/2.8: impact injury

[Bjørn Rørslett]

We indeed share the experience ....

I recently got a stack of Nikon bayonet mounts from my friendly Nikon repair tech, all of them being the torn-off rear part of 24-70 lenses. So indeed this works in practice and actually saves the unfortunate user from getting a damaged camera and associated huge repair bills.

Busy (and careless) press photographers enjoy the quick repair fix if you have NPS membership. My Nikon contacts tell me the repair by swapping the broken rear component by a factory spare can be easily done between the two halves of a football ('soccer' to some) match.

[stenrasmussen]

Well, I just couldn't keep my hands off this lens. Disassembled it further this time and man...a previous owner has really tampered with it:
Chipped and scratched the rear side of the 4th lens group, bent the M/A focus brush, sanded(!) the inside and flanges of the rear fixed house (the part that sits just behind the zoom ring), marred screw heads, etc. Basically a wreck but I managed to get it back to kind of acceptable condition, i.e. smooth operation of zoom/focus rings, decentering less pronounced and autofocus less erratic.
Another weak design: The mainboards are secured with one screw only, increasing the chance of misalignment of the boards so one/both touches the rotating part of the SWM. If it touchdown happens a squeeky noise fills your ears.
Attached is a pic showing the chipped 4th lens group.

[Erik Lund]

This is the worst I have seen... ouch 

[stenrasmussen]

This is the worst I have seen... ouch 

I guess some lens explorers are less cautious...l or should I say, "I-know-this-will-end-badly-but-what-the-hell"

[Erik Lund]

Some of the most fragile parts are the sliding contacts that are used for the read out of distance and focal length intervals, they are so tiny and thin... That's one of the reasons I try to stay away from messing with AF lenses. But how manage to do this internally to the glass, it must have been a war zone    ...

[Bjørn Rørslett]

The "repair man" probably used hammer and chisel or suchlike tools ...

[stenrasmussen]

Here's the one of the two main boards. The gap towards the rotating black ring (to the upper left) is not large.
The brushes are fragile...and here's the bent example from said lens:

[stenrasmussen]

I don't have a pic of the inside of the rear housing but I tell you...a desperate war must have played out there with tools to fit the "(un)intended" damage.

[Erik Lund]

Looks like the main board is not correctly mounted...

[stenrasmussen]

Looks like the main board is not correctly mounted...

If you are looking at available space above the screw (to the right on the image) you are right. But the shown position is as far up as it goes.