Tech Story - Sony NEX-5N crash and fix - "unable to use memory card - Format?"

Last night - good filming session on project "Brave Love".

Today - problem.  Number one camera, Sony NEX-5N giving strange problems leading to a complete crash.

Fix.  Change the battery.

Insight.  This happened with my number 2 battery running low giving strange problems rather than useful warning messages.  Number 2 battery is a low cost 3rd party pattern battery.  Good service for 2 years but now this.

On changing the battery, everything came right.

Does this mean avoid 3rd party batteries?  I don't think so.  We just need to be aware that the "pattern" battery can give strange results when it is running low and the fix is to charge and/or change the battery.

What are these "strange problems"?

1.  I tried an experiment to shoot test video with "precision digital zoom".
(Aside, I know it does not make normal logical sense to do this but this is a special case where I wanted to try out some vintage c-mount lenses on the NEX.)  The video recording froze. Here was the classic case of the battery going low co-inciding with an unusual experiment so I lose a lot of time assuming that the event is connected with the unusual experiment.


2.  Repeating message on-screen.

"unable to use memory card
Format?"

This message does not make sense because there is only a "no" option with no way of responding with a "yes".

This message alternated with
"re-insert memory card"

3.   Dim-light dead
After some repeats of 2 above, NEX got into a state where switch the camera on, and the lcd screen lights up slightly, ie slightly lighter than the black of the off state.  And nothing else.  That one had me thinking battery.  Change batteries and everything recovered.

This may seem like a trivial and obvious piece of knowledge, but on running the Google search "unable to use memory card - Format?", I did not find useful information so maybe it is useful to put this into the internet mix with the contribution - "low battery - charge and/or change it!".

Thought experiment! The follow-up experiment which I do not have time to do would be to run an equally aged official battery to a low level and see if it delivers the same or more graceful behaviour.

And what about that play with old c-mount lenses?  With a battery change I discover that this is for stills only. Any "precision digital zoom" setting disappears when I press the video record button.