There were several reports on both Android Forums and HowardForums of problems with the Motorola DROID’s autofocus. Yesterday, the issue seemed to resolve itself, without warning.

At first users believed that Motorola had fixed the problem by pushing a silent firmware update which fixed the issue. But, it turns out that due to a very odd software bug, the Motorola DROID’s autofocus goes through cycles of good and bad performance. Every 24.5 days it will experience a shift in performance quality one way or the other.

We’re currently in one of the good cycles but a fix should be out by December 11, when the next shift would happen.

Google’s Dan Morrill explains it best in Engadget’s comments:

There’s a rounding-error bug in the camera driver’s autofocus routine (which uses a timestamp) that causes autofocus to behave poorly on a 24.5-day cycle. That is, it’ll work for 24.5 days, then have poor performance for 24.5 days, then work again.

The 17th is the start of a new “works correctly” cycle, so the devices will be fine for a while. A permanent fix is in the works.

What an odd bug.