subminiature

Short definition from Wiktionary

Adjective

1. 1
   Compact or smaller than miniature.
2. 2
   of photography equipment and techniques using a smaller frame than 35mm

Noun

1. 1
   Any item smaller than that considered miniature, especially electronic and electromechanical devices
2. 2
   A subminiature camera, generally with a frame smaller than 35mm