2D MATRIX - BRIGHT FIELD
Image of a 2D matrix (Bumpy Barcode) pin stamped in to metal. This image demonstrates the bright field technique where the majority of the picture is bright and pits being read are darker. This effect is accomplished by aiming the light directly at the part.
This picture was taken with a 25mm lens plus 1mm spacer with the aperature closed down about half way and exposed for 0.7ms.