Camera not shutting down correctly with intervalometer when battery dies

Issue #2221 open
clombard
created an issue

Canon 7D with magiclantern-Nightly.2015Mar02.7D203

I used the intervalometer twice for some dayshots this weekend, just letting it run until it ran out of of battery power. Each time, when I switched the camera on again with a fresh battery, it complained that it did not shut down correctly and then loaded the default (i.e. not ML) firmware.

One of the other guys in our group commented that this has caused a corrupted memory card for him in the past.

Comments (13)

  1. Alex

    Do you know if the camera stopped in the middle of taking a picture, or while waiting before 2 pictures?

    The 7D had this problem from the beginning, so ML uses an workaround at the end of each picture.

    Can you reproduce the issue by taking the battery out manually in the middle of an intervalometer sequence? It's not funny to debug by waiting until the battery gets emtpy.

  2. clombard reporter

    Unfortunately I don't know precisely where it stopped, but, yes, I could reproduce it this morning by opening the battery compartment. The camera started up again with a complaint that it didn't shut down correctly and "couldn't load the module", like on the weekend.

    Not sure what the last error meant as it loaded ML and started shooting again. Think I misunderstood what "module" meant with the previous timelapses; sorry about that.

  3. Alex

    After reading it a second time, I figured out what you meant. After a crash, modules are not loaded, and this is normal.

    You can change this behavior from the Debug menu.

  4. clombard reporter

    Problem comes in when that is not possible. Timelapse is taken in very out of the way places and people fall asleep. I can't really take the chance of a corrupted memory card, so better not use ML. Thanks in any case.

  5. Alex

    Indeed, if the battery empties in the middle of a file write operation, filesystem corruption may occur.

    It's also worth trying another battery. Some batteries may get empty before the CPU detects this condition (especially if they are old).

    As a workaround, ML could be programmed to refuse to take pictures if the battery is say less than 2%. This should help.

  6. clombard reporter

    The workaround would be great.

    I'll try all 3 my batteries. Two are generic, but that shouldn't be an issue I think; the camera picks them up properly.

  7. Alex

    My old laptop used to shut down abruptly (power loss) when the battery indicator was around 10%. I wouldn't be surprised if some cheap or worn-out batteries would behave in the same way.

  8. clombard reporter

    Wonder how the camera usually knows it is going to shut down soon? Assuming that information isn't readily available, it might be a good idea to make the percentage configurable.

    All three batteries I have usually goes the full range of %; haven't had any problems with them so far. I'll do a couple of tests with them tonight to check if there's any difference in behaviour.

    Are there any specific tests you would like me to run?

  9. clombard reporter

    All three batteries are behaving in the same way.

    By the way, I'm seeing the same behaviour when the battery goes flat when doing lightning photographs with light difference detection.

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