Two broken screws

Today’s picture is something of an experiment.  I wanted to see just how small an item I could photograph.  As a reference the graduations at the top of the image are mm markings on a ruler.

The story behind the photo: I was repairing a  dining room chair today, and both of these screws broke as I was screwing them in, leaving the threaded part emedded in the wood of the chair.

For the photographers a few technical bits about the shot.  105mm macro lens + every extension tube I own.  Appature F45 to get the depth of field.  Exposure time: 6 minutes (yes I do mean minutes).