Chosen Solution
A Nikon D3200 stopped autofocusing. Going in the clean the AF sensor (yes, that was the issue, we tested several different lenses on different bodies) we found this odd thing sticking up from the bottom.
Additionally, there is at least one more.
here’s a separate camera that shows this isn’t there:
checked across 3 cameras, the weird one is the only one with any of this going on.
These are iris blades to cover the auto focus/metering detector from dust. When your reflex mirror is in the down position a second mirror unfolds just underneath to aim the light down to this sensor.
