I searched for answers on why my autofocus stopped working for my Nikon D750.

I found that someone posted:

“Note that when using AF lenses that are not AF-S lenses the AF/M switch on the camera body just below the lens release should not be set to "AF" if the lens is set to "M." Using the camera in such a situation can damage either the lens or the camera. The warning is on page 132”

I believe this is what I did. Now autofocus doesn’t work on any lens I use. Can this be repaired or replaced under my warranty?

  • \$\begingroup\$ Getting a warranty repair for something you know you mis-operated is ethically a very grey area. Please don't play games like "feigning ignorance and communicating dissatisfaction" on local brick and mortar dealers, you make it worse for everyone. \$\endgroup\$ Commented May 8, 2019 at 13:27
  • \$\begingroup\$ That seems like an absolute junk design decision. Then again, I've got a few cameras in my cabinet that also have some pretty stringent order of operations requirements... \$\endgroup\$
    – OnBreak.
    Commented May 8, 2019 at 23:32
  • 2
    \$\begingroup\$ Voting to close as opinion based. No one but Nikon knows if they'll honor a warranty claim for this. It doesn't hurt to contact them and ask and/or ask your local Nikon dealer. \$\endgroup\$
    – OnBreak.
    Commented May 8, 2019 at 23:36
  • \$\begingroup\$ Also, somebody could put themselves in hot water posting that kind of scenario here... then attempting it nevertheless (and maybe crossing the line into warranty fraud). \$\endgroup\$ Commented May 9, 2019 at 17:02
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    \$\begingroup\$ What lens were you using when you think you body switch to 'AF' while the lens was set to 'M'? \$\endgroup\$
    – Michael C
    Commented May 9, 2019 at 17:28

2 Answers 2


It looks as though you've seen Michael C's response to "Why is my Nikon D750 not autofocusing?". If you've not already double checked all of those settings though, it's worth making sure that none of them could be the reason that autofocus isn't working, even if you don't think there's any possibility that you changed them.

The reason Nikon give that warning is because setting the camera mode to "M" retracts the screw that drives the autofocus to the lens. If the screw is left engaged, then turning the focus ring of an AF lens by hand will also turn the screw which can damage the motor. It seems that AF-S lenses have a different internal design which allows them to bypass the screw when the lens is set to "M", so it doesn't matter so much if the screw is retracted or not.

You can certainly enquire about having your camera repaired, but if as you suspect the damage was caused by ignoring (or missing the significance) of a warning that's printed in the guide supplied with the camera, it's unlikely that Nikon would agree to fix it under warranty (based on my reading of the UK (my region) repair centre T&Cs). You should be able to ask for an estimate first if you'd like to get an idea of the cost before proceeding, though.


If this problem isn't in other Nikon models and the warning wasn't in big red highlighted writing then I think a Judge might rule in your favour. The small claims court would certainly be worth considering.


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